Prominins (proms) are transmembrane glycoproteins conserved throughout the animal kingdom. They are associated with plasma membrane protrusions, such as primary cilia, as well as extracellular vesicles derived thereof. Primary cilia host numerous signaling pathways affected in diseases known as ciliopathies. Human PROM1 (CD133) is detected in both somatic and cancer stem cells and is also expressed in terminally differentiated epithelial and photoreceptor cells. Genetic mutations in the PROM1 gene result in retinal degeneration by impairing the proper formation of the outer segment of photoreceptors, a modified cilium. Here, we investigated the impact of proms on two distinct examples of ciliogenesis. First, we demonstrate that the overexpression of a dominant-negative mutant variant of human PROM1 (i.e. mutation Y819F/Y828F) significantly decreases ciliary length in Madin–Darby canine kidney cells. These results contrast strongly to the previously observed enhancing effect of WT PROM1 on ciliary length. Mechanistically, the mutation impeded the interaction of PROM1 with ADP-ribosylation factor–like protein 13B, a key regulator of ciliary length. Second, we observed that in vivo knockdown of prom3 in zebrafish alters the number and length of monocilia in the Kupffer's vesicle, resulting in molecular and anatomical defects in the left-right asymmetry. These distinct loss-of-function approaches in two biological systems reveal that prom proteins are critical for the integrity and function of cilia. Our data provide new insights into ciliogenesis and might be of particular interest for investigations of the etiologies of ciliopathies.

The action mechanisms revealed by the biochemical and structural analyses of replicative and translesion synthesis (TLS) DNA polymerases (Pols) are retained in their cellular roles. In this regard, DNA polymerase θ differs from other Pols in that whereas purified Polθ misincorporates an A opposite 1,N6-ethenodeoxyadenosine (ϵdA) using an abasic-like mode, Polθ performs predominantly error-free TLS in human cells. To test the hypothesis that Polθ adopts a different mechanism for replicating through ϵdA in human cells than in the purified Pol, here we analyze the effects of mutations in the two highly conserved tyrosine residues, Tyr-2387 and Tyr-2391, in the Polθ active site. Our findings that these residues are indispensable for TLS by the purified Pol but are not required in human cells, as well as other findings, provide strong evidence that the Polθ active site is reconfigured in human cells to stabilize ϵdA in the syn conformation for Hoogsteen base pairing with the correct nucleotide. The evidence that a DNA polymerase can configure its active site entirely differently in human cells than in the purified Pol establishes a new paradigm for DNA polymerase function.

We previously reported that overexpression of cytochrome P450 family 24 subfamily A member 1 (CYP24A1) increases lung cancer cell proliferation by activating RAS signaling and that CYP24A1 knockdown inhibits tumor growth. However, the mechanism of CYP24A1-mediated cancer cell proliferation remains unclear. Here, we conducted cell synchronization and biochemical experiments in lung adenocarcinoma cells, revealing a link between CYP24A1 and anaphase-promoting complex (APC), a key cell cycle regulator. We demonstrate that CYP24A1 expression is cell cycle–dependent; it was higher in the G2-M phase and diminished upon G1 entry. CYP24A1 has a functional destruction box (D-box) motif that allows binding with two APC adaptors, CDC20-homologue 1 (CDH1) and cell division cycle 20 (CDC20). Unlike other APC substrates, however, CYP24A1 acted as a pseudo-substrate, inhibiting CDH1 activity and promoting mitotic progression. Conversely, overexpression of a CYP24A1 D-box mutant compromised CDH1 binding, allowing CDH1 hyperactivation, thereby hastening degradation of its substrates cyclin B1 and CDC20, and accumulation of the CDC20 substrate p21, prolonging mitotic exit. These activities also occurred with a CYP24A1 isoform 2 lacking the catalytic cysteine (Cys-462), suggesting that CYP24A1's oncogenic potential is independent of its catalytic activity. CYP24A1 degradation reduced clonogenic survival of mutant KRAS-driven lung cancer cells, and calcitriol treatment increased CYP24A1 levels and tumor burden in Lsl-KRASG12D mice. These results disclose a catalytic activity-independent growth-promoting role of CYP24A1 in mutant KRAS-driven lung cancer. This suggests that CYP24A1 could be therapeutically targeted in lung cancers in which its expression is high.

The traditionally blue-collar neighbourhood of Sham Shui Po is home to a kaleidoscopic collection of landmarks, streets and shops.

Participants of the Sham Shui Po Ensemble project explored the area and told its story through video and music production.

One of the project’s creative productions, the short film Collage created by Cobe Yau and her team, documented the daily lives of the area’s residents.

Ms Yau said Sham Shui Po’s diversity inspired her team to combine footage of residents’ daily activities, such as the unloading of meat and vegetables in wet markets and hawkers selling their wares.

“We hope our viewers can realise that although there are some street sleepers and it may be a bit grimy in some parts of Sham Shui Po, there are also many interesting aspects that make this community stand out.”

Creative journeys

Sham Shui Po Ensemble is under the Community Record Company, an 18-month community-based programme which also showcases two other unique locales.

Last year, participants explored Sai Ying Pun under the West Side Re-Discovery project. Sham Shui Po Ensemble was launched in April and concluded in late July, while the Wander in To Kwa Wan project began this month.

Local documentary maker Wong Siu-pong, the Community Curator of the Sham Shui Po project, hopes participants are able to explore the community without bias.

“Apart from the basics of film production, I did not teach them a lot of filmmaking skills. I hope they learn to be humble when making a documentary.

“A lot of the time, we read the news to learn about a community. I hope they can discover these places without prejudice, this is important.”

Project participants were also able to paint a picture of the community with music.

Warren Luk joined the project’s music stream and wrote the song Rich on Life with his team.

“People always have preconceived ideas of Sham Shui Po. But when you walk through the neighbourhood, you can find lots of quirky and interesting landmarks.

“When you observe the interactions between residents there, you can see that although their lives may be tough, they are enjoying themselves a lot. It is very inspiring.”

The Community Record Company programme is organised by non-governmental organisation MaD Institute and sponsored by the Home Affairs Bureau’s Arts Capacity Development Funding Scheme, which seeks to strengthen Hong Kong’s cultural software and build up the arts sector.

Application details for the next funding exercise will be available in November.

(Impact Journals LLC) Volume 11, Issue 18 of @Oncotarget Clinical implications of chromatin accessibility assessed by ATAC-seq profiling in human cancers especially in a large patient cohort is largely unknown.

(Memorial Sloan Kettering Cancer Center) Scientists at the Sloan Kettering Institute have solved the puzzle of how small chromosomes ensure that they aren't skipped over during meiosis, the process that makes sperm and egg.

(University of Helsinki) Mutations in white blood cells can contribute to abnormal immune profile after hematopoietic stem cell transplantation.

(Cell Press) In a study appearing April 30 in the journal Current Biology, scientists tell the story of three 16th century African slaves identified from a mass burial site in Mexico City. Using a combination of genetic, osteological, and isotope analyses, the scientists determined from where in Africa they were likely captured, the physical hardships they experienced as slaves, and what novel pathogens they may have carried with them across the Atlantic.

(University of Chicago Press Journals) Extensive cooperation among biologically unrelated individuals is uniquely human. It would be surprising if this uniqueness were not related to other uniquely human characteristics, yet current theories of human cooperation tend to ignore the human aspects of human behavior. This paper presents a theory of cooperation that draws on social, cultural, and psychological aspects of human uniqueness for which current theories have little or no explanation.

(University of Adelaide) An international team of scientists led by the University of Adelaide's Davies Research Centre has shown that it is possible to disentangle the DNA sequences of the chromosomes inherited from the mother and the father, to create true diploid genomes from a single individual.

(Earth Institute at Columbia University) A uniquely resilient organism all but unheard of in the Arabian Sea 20 years ago has been proliferating and spreading at an alarming pace. New research describes how the continued loss of snow over the Himalayan-Tibetan Plateau region is fueling the expansion of this destructive algal bloom.

(Brown University) A new study shows that coastal sea ice used by Arctic residents for hunting and fishing will be reduced as the planet warms.

(University of Hawaii at Manoa) In a study published in Scientific Reports, researchers at the University of Hawai'i at Mānoa, found in the next few decades, sea level rise will likely cause large and increasing percentages of land area to be impacted simultaneously by the three flood mechanisms. Further, they found direct marine inundation represents the least extensive--only three percent of the predicted flooding, while groundwater inundation represents the most extensive flood source.

Apr 1, 2004; 17:97-101
Articles

Management professors Adam Galinksy and Paul Ingram, together with Jonathan Laor ’21, CEO of Applicaster, advise on leadership during a crisis.

6 March 2016

As part of a roundtable series, Chatham House, China University of Political Science and Law (CUPL) and the Graduate Institute Geneva held a two-day roundtable meeting in Geneva on public international law and the rights of individuals.

Invitation Only Research Event

Event participants

Chair: Elizabeth Wilmshurst, Distinguished Fellow, International Law Programme, Chatham House

Beatriz Rocha
Apr 1, 2020; 19:574-588
Research

Georg H H Borner
Apr 28, 2020; 0:R120.001971v1-mcp.R120.001971
Review

Guest blog by Stephen McKean On my first day of college, I showed up an hour early to my very first class. The class was Math 2210, multivariable calculus. For some reason, I thought this was the highest math class … Continue reading →

Invitation Only Research Event

7 January 2020

26 February 2020

Over the past two decades, China has increased its presence in North Africa in terms of trade and investment. This paper looks at China’s policy within the context of its Africa and Middle East policies to better understand its approach to Morocco and Tunisia.

Objectives: The study compared the diagnostic performance of Planar Ventilation/perfusion (V/Q) and V/Q Single-photon computed tomography (SPECT), and determined whether combining perfusion scanning with low-dose computed tomography (Q-LDCT) may be equally effective in a prospective study of patients with chronic thromboembolic pulmonary hypertension (CTEPH) patients. Background: V/Q scanning is recommended for excluding CTEPH during the diagnosis of pulmonary hypertension (PH). However, Planar V/Q and V/Q SPECT techniques have yet to be compared in patients with CTEPH. Methods: Patients with suspected PH were eligible for the study. PH attributable to left heart disease or lung disease was excluded, and patients whose PH was confirmed by right heart catheterization and who completed Planar V/Q, V/Q-SPECT, Q-LDCT, and pulmonary angiography were included. V/Q images were interpreted and patients were diagnosed as instructed by the 2009 EANM guidelines, and pulmonary angiography analyses were used as a reference standard. Results: A total of 208 patients completed the study, including 69 with CTEPH confirmed by pulmonary angiography. Planar V/Q, V/Q-SPECT, and Q-LDCT were all highly effective for diagnosing CTEPH, with no significant differences in sensitivity or specificity observed among the three techniques (Planar V/Q [sensitivity/specificity]: 94.20%/92.81%; V/Q-SPECT: 97.10%/91.37%, Q-LCDT: 95.65%/90.65%). However, V/Q-SPECT was significantly more sensitive (V/Q-SPECT: 79.21%; Planar V/Q: 75.84%, P = 0.012; Q-LDCT: 74.91%, p<0.001), and Planar V/Q was significantly more specific (Planar V/Q: 54.14%; V/Q-SPECT 46.05%, p<0.001; Q-LDCT: 46.05%, P = 0.001) than the other two techniques for identifying perfusion defects in individual lung segments. Conclusion: Both Planar V/Q and V/Q-SPECT were highly effective for diagnosing CTEPH, and Q-LDCT may be a reliable alternative method for patients who are unsuitable for ventilation imaging.

6 November 2019 , Volume 95, Number 6

Triple-negative breast cancer (TNBC) is characterized by poor response to therapy and low overall patient survival. Recently, Estrogen Receptor beta (ERβ) has been found to be expressed in a fraction of TNBCs where, because of its oncosuppressive actions on the genome, it represents a potential therapeutic target, provided a better understanding of its actions in these tumors becomes available. To this end, the cell lines Hs 578T, MDA-MB-468 and HCC1806, representing the claudin-low, basal-like 1 and 2 TNBC molecular subtypes respectively, were engineered to express ERβ under the control of a Tetracycline-inducible promoter and used to investigate the effects of this transcription factor on gene activity. The antiproliferative effects of ERβ in these cells were confirmed by multiple functional approaches, including transcriptome profiling and global mapping of receptor binding sites in the genome, that revealed direct negative regulation by ERβ of genes, encoding for key components of cellular pathways associated to TNBC aggressiveness representing novel therapeutic targets such as angiogenesis, invasion, metastasis and cholesterol biosynthesis. Supporting these results, interaction proteomics by immunoprecipitation coupled to nano LC-MS/MS mass spectrometry revealed ERβ association with several potential nuclear protein partners, including key components of regulatory complexes known to control chromatin remodeling, transcriptional and post-transcriptional gene regulation and RNA splicing. Among these, ERβ association with the Polycomb Repressor Complexes 1 and 2 (PRC1/2), known for their central role in gene regulation in cancer cells, was confirmed in all three TNBC subtypes investigated, suggesting its occurrence independently from the cellular context. These results demonstrate a significant impact of ERβ in TNBC genome activity mediated by its cooperation with regulatory multiprotein chromatin remodeling complexes, providing novel ground to devise new strategies for the treatment of these diseases based on ligands affecting the activity of this nuclear receptor or some of its protein partners.

Mycobacterial Ser/Thr protein kinases (STPKs) play a critical role in signal transduction pathways that ultimately determine mycobacterial growth and metabolic adaptation. Identification of key physiological substrates of these protein kinases is, therefore, crucial to better understand how Ser/Thr phosphorylation contributes to mycobacterial environmental adaptation, including response to stress, cell division, and host-pathogen interactions. Various substrate detection methods have been employed with limited success, with direct targets of STPKs remaining elusive. Recently developed mass spectrometry (MS)-based phosphoproteomic approaches have expanded the list of potential STPK substrate identifications, yet further investigation is required to define the most functionally significant phosphosites and their physiological importance. Prior to the application of MS workflows, for instance, GarA was the only known and validated physiological substrate for protein kinase G (PknG) from pathogenic mycobacteria. A subsequent list of at least 28 candidate PknG substrates has since been reported with the use of MS-based analyses. Herein, we integrate and critically review MS-generated datasets available on novel STPK substrates and report new functional and subcellular localization enrichment analyses on novel candidate protein kinase A (PknA), protein kinase B (PknB) and PknG substrates to deduce the possible physiological roles of these kinases. In addition, we assess substrate specificity patterns across different mycobacterial STPKs by analyzing reported sets of phosphopeptides, in order to determine whether novel motifs or consensus regions exist for mycobacterial Ser/Thr phosphorylation sites. This review focuses on MS-based techniques employed for STPK substrate identification in mycobacteria, while highlighting the advantages and challenges of the various applications.

For more than two decades naturally presented, human leukocyte antigen (HLA)-restricted peptides (immunopeptidome) have been eluted and sequenced using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Since, identified disease-associated HLA ligands have been characterized and evaluated as potential active substances. Treatments based on HLA-presented peptides have shown promising results in clinical application as personalized T cell-based immunotherapy. Peptide vaccination cocktails are produced as investigational medicinal products under GMP conditions. To support clinical trials based on HLA-presented tumor-associated antigens, in this study the sensitive LC-MS/MS HLA class I antigen identification pipeline was fully validated for our technical equipment according to the current US Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines.

The immunopeptidomes of JY cells with or without spiked-in, isotope labeled peptides, of peripheral blood mononuclear cells of healthy volunteers as well as a chronic lymphocytic leukemia and a bladder cancer sample were reliably identified using a data-dependent acquisition method. As the LC-MS/MS pipeline is used for identification purposes, the validation parameters include accuracy, precision, specificity, limit of detection and robustness.

In osteoarthritis (OA), impairment of cartilage regeneration can be related to a defective chondrogenic differentiation of mesenchymal stromal cells (MSCs). Therefore, understanding the proteomic- and metabolomic-associated molecular events during the chondrogenesis of MSCs could provide alternative targets for therapeutic intervention. Here, a SILAC-based proteomic analysis identified 43 proteins related with metabolic pathways whose abundance was significantly altered during the chondrogenesis of OA human bone marrow MSCs (hBMSCs). Then, the level and distribution of metabolites was analyzed in these cells and healthy controls by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), leading to the recognition of characteristic metabolomic profiles at the early stages of differentiation. Finally, integrative pathway analysis showed that UDP-glucuronic acid synthesis and amino sugar metabolism were downregulated in OA hBMSCs during chondrogenesis compared with healthy cells. Alterations in these metabolic pathways may disturb the production of hyaluronic acid (HA) and other relevant cartilage extracellular matrix (ECM) components. This work provides a novel integrative insight into the molecular alterations of osteoarthritic MSCs and potential therapeutic targets for OA drug development through the enhancement of chondrogenesis.

The respiratory epithelium comprises polarized cells at the interface between the environment and airway tissues. Polarized apical and basolateral protein secretions are a feature of airway epithelium homeostasis. Human respiratory syncytial virus (hRSV) is a major human pathogen that primarily targets the respiratory epithelium. However, the consequences of hRSV infection on epithelium secretome polarity and content remain poorly understood. To investigate the hRSV-associated apical and basolateral secretomes, a proteomics approach was combined with an ex vivo pediatric human airway epithelial (HAE) model of hRSV infection (data are available via ProteomeXchange and can be accessed at https://www.ebi.ac.uk/pride/ with identifier PXD013661). Following infection, a skewing of apical/basolateral abundance ratios was identified for several individual proteins. Novel modulators of neutrophil and lymphocyte activation (CXCL6, CSF3, SECTM1 or CXCL16), and antiviral proteins (BST2 or CEACAM1) were detected in infected, but not in uninfected cultures. Importantly, CXCL6, CXCL16, CSF3 were also detected in nasopharyngeal aspirates (NPA) from hRSV-infected infants but not healthy controls. Furthermore, the antiviral activity of CEACAM1 against RSV was confirmed in vitro using BEAS-2B cells. hRSV infection disrupted the polarity of the pediatric respiratory epithelial secretome and was associated with immune modulating proteins (CXCL6, CXCL16, CSF3) never linked with this virus before. In addition, the antiviral activity of CEACAM1 against hRSV had also never been previously characterized. This study, therefore, provides novel insights into RSV pathogenesis and endogenous antiviral responses in pediatric airway epithelium.

Cyber attacks have labelled the number one threat to power and utility companies worldwide, a new EY report has found.

In this week's UK Tech Weekly Podcast host Matt Egan is joined by PC Advisor staff writer Chris Minasians chats about Facebook's new like buttons, the team has contracted smartphone fever from the Mobile World Conference in Barcelona and finally, acting editor of Macworld UK David Price, discusses Donald Trump boycotting Apple.  

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In this week's fiery episode host Matt Egan talks war and gaming with Macworld UK's David Price, the greatest graphics ever with Christopher Minasians of PC Advisor and Macworld UK (14:21), and the best networks in the UK with fellow PCA and MWUK stalwart Henry Burrell (25:23). Expect songs and laughter, and tech ever after.  

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This week David Price is in the presenter chair for the jolliest tech podcast of the year. David is joined by Miriam Harris, staff writer at Digital Arts, to talk about the design trends set to shape 2017. Then online editor at Techworld Scott Carey runs through the hottest tech gifts this Christmas, including games consoles, VR, Amazon gadgets and Star Wars merch (14:30). Finally, staff writer at PC Advisor Dom Preston makes his UKTW debut to chat about the latest Star Wars movie, Rogue One, which includes spoilers (29:00). This is the last UK Tech Weekly podcast of the year. Thank you for listening and we will be back in 2017 to chat about the hottest tech topics all over again.  

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We finally get the IoT acronym the pod has been waiting for as we discuss Bitcoin and 17th century Dutch finance. Charlotte Jee informs Henry Burrell, David Price and Scott Carey.

Scott then leads us down the winding road of the so-called platform wars, in a week when Google blocked the Amazon Echo Show from streaming YouTube. Is this a bump in the road or will services be cut from rival hardware?

And finally, led by David, the pod discusses its favourite tech of the year and what you might consider buying for friends and family for Christmas.

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Once more for 2017 as Henry Burrell, Karen Khan and Scott Carey bid farewell to this wonderful year (ahem) with musings on Apple's sexy new iMac Pro. Who is it for, how much is it and does this mean there is no Mac Pro in 2018?

We then tackle Netflix's Twitter shaming of its users and why Spotify got away with it earlier in the year. How comfortable are we all when we realise how much data companies really have on us?

In light of this, Apple bought Shazam - most likely for the data sets as much as the tech and the talent. What form will it take in Apple as another UK tech company is acquired?

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Scott Carey leads veteran Henry Burrell and first time podder Hannah Williams down the rabbit hole of Google I/O. We discuss which was the most frightening announcement and which was the best - could that actually be the same thing?

We then chat Android P, the beta for Google next OS - cool changes, yes, but how many people will actually ever get it?

Scott and Hannah also weigh in on why Google gets the headlines despite Facebook, Microsoft and Amazon announcements this week.

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Two’s a crowd for this week’s games and Christmas pod with Consumer Tech Editor Henry Burrell and Games Editor Lewis Painter. Lewis lines up reviews of the awful Fallout 76 and the excellent online mode of Red Dead Redemption 2 – two polar opposites in how to make a decent online multiplayer game.

We also discuss smartwatches we’ve recently reviewed that left us feeling cold and why Apple is still king of the hill.

And to get into the festive vibe, interspersed throughout as we enter December are our top tech Christmas gift picks, both cheap and indulgent.

Everything we recommend is linked below:

Google Home Hub

Tile Bluetooth tracker

Red Dead Redemption 2 (PS4)

Super Smash Bros – Ultimate (Switch)

Pokémon: Let’s Go, Pikachu! (Switch)

Turtle Beach Elite Pro 2 + Superamp

Amazon Kindle Paperwhite

PlayStation Classic

PlayStation VR Starter Pack

The best budget smartphones

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Withdrawn by Author.

The histidine kinase Hik33 plays important roles in mediating cyanobacterial response to divergent types of abiotic stresses including cold, salt, high light (HL), and osmotic stresses. However, how these functions are regulated by Hik33 remains to be addressed. Using a hik33-deficient strain (hik33) of Synechocystis sp. PCC 6803 (Synechocystis) and quantitative proteomics, we found that Hik33 depletion induces differential protein expression highly similar to that induced by divergent types of stresses. This typically includes downregulation of proteins in photosynthesis and carbon assimilation that are necessary for cell propagation, and upregulation of heat shock proteins, chaperons, and proteases that are important for cell survival. This observation indicates that depletion of Hik33 alone mimics divergent types of abiotic stresses, and that Hik33 could be important for preventing abnormal stress response in the normal condition. Moreover, we found the majority of proteins of plasmid origin were significantly upregulated in hik33, though their biological significance remains to be addressed. Together, the systematically characterized Hik33-regulated cyanobacterial proteome, which is largely involved in stress responses, builds the molecular basis for Hik33 as a general regulator of stress responses.

Protein subcellular localization is an essential and highly regulated determinant of protein function. Major advances in mass spectrometry and imaging have allowed the development of powerful spatial proteomics approaches for determining protein localization at the whole cell scale. Here, a brief overview of current methods is presented, followed by a detailed discussion of organellar mapping through proteomic profiling. This relatively simple yet flexible approach is rapidly gaining popularity, due to its ability to capture the localizations of thousands of proteins in a single experiment. It can be used to generate high-resolution cell maps, and as a tool for monitoring protein localization dynamics. This review highlights the strengths and limitations of the approach, and provides guidance to designing and interpreting profiling experiments. 

1 March 2007 , Number 11

In early November, the retiring head of Britain’s Security Service MI5, Dame Eliza Manningham-Buller, warned that the danger of a terror attack was ‘serious’ and ‘growing’, with as many as thirty plots underway. Traditional terrorism of the sort practised by the Irish Republican Army has given way to the possibility, if not the expectation, that groups such as Al Qaeda might make use of chemical, biological, radiological and nuclear weapons and materials in an attack in Britain. So what are the dangers?

28 November 2019

21 January 2020

4 February 2020

Treatment of patients with chronic lymphocytic leukemia (CLL) with inhibitors of Bruton's tyrosine kinase (BTK), such as ibrutinib, is limited by primary or secondary resistance to this drug. Examinations of CLL patients with late relapses while on ibrutinib, which inhibits BTK's catalytic activity, revealed several mutations in BTK, most frequently resulting in the C481S substitution, and disclosed many mutations in PLCG2, encoding phospholipase C-γ2 (PLCγ2). The PLCγ2 variants typically do not exhibit constitutive activity in cell-free systems, leading to the suggestion that in intact cells they are hypersensitive to Rac family small GTPases or to the upstream kinases spleen-associated tyrosine kinase (SYK) and Lck/Yes-related novel tyrosine kinase (LYN). The sensitivity of the PLCγ2 variants to BTK itself has remained unknown. Here, using genetically-modified DT40 B lymphocytes, along with various biochemical assays, including analysis of PLCγ2-mediated inositol phosphate formation, inositol phospholipid assessments, fluorescence recovery after photobleaching (FRAP) static laser microscopy, and determination of intracellular calcium ([Ca2+]i), we show that various CLL-specific PLCγ2 variants such as PLCγ2S707Y are hyper-responsive to activated BTK, even in the absence of BTK's catalytic activity and independently of enhanced PLCγ2 phospholipid substrate supply. At high levels of B-cell receptor (BCR) activation, which may occur in individual CLL patients, catalytically-inactive BTK restored the ability of the BCR to mediate increases in [Ca2+]i. Because catalytically-inactive BTK is insensitive to active-site BTK inhibitors, the mechanism involving the noncatalytic BTK uncovered here may contribute to preexisting reduced sensitivity or even primary resistance of CLL to these drugs.

HLA-DQA1 and -DQB1 are strongly associated with type 1 diabetes (T1D), and DQ8.1 and DQ2.5 are major risk haplotypes. Next generation targeted sequencing of HLA-DQA1 and -DQB1 in Swedish newly diagnosed 1-18 year-old patients (n=962) and controls (n=636) was used to construct abbreviated DQ haplotypes, converted into amino acid (AA) residues, and assessed for their associations with T1D. A hierarchically-organized haplotype (HOH) association analysis, allowed 45 unique DQ haplotypes to be categorized into seven clusters. The DQ8/9 cluster included two DQ8.1 risk and the DQ9 resistant haplotypes, and the DQ2 cluster, included the DQ2.5 risk and DQ2.2 resistant haplotypes. Within each cluster, HOH found residues α44Q (OR 3.29, p=2.38*10^-85 ) and β57A (OR 3.44, p=3.80*10^-84) to be associated with T1D in the DQ8/9 cluster representing all ten residues (α22, α23, α44, α49, α51, α53, α54, α73, α184, β57) due to complete linkage-disequilibrium (LD) of α44 with eight such residues. Within the DQ2 cluster and due to LD, HOH analysis found α44C and β135D to share the risk for T1D (OR 2.10, p=1.96*10^-20). The motif "QAD" of α44, β57, and β135 captured the T1D risk association of DQ8.1 (OR 3.44, p=3.80*10^-84), the corresponding motif "CAD" captured the risk association of DQ2.5 (OR 2.10, p=1.96*10^-20). Two risk associations were related to GADA and IA-2A, but in opposite directions. "CAD" was positively associated with GADA (OR 1.56; p=6.35*10^-8) but negatively with IA-2A (OR 0.59, p= 6.55*10^-11). "QAD" was negatively associated with GADA (OR 0.88; p= 3.70*10^-3) but positively with IA-2A (OR 1.64; p= 2.40*10^-14), despite a single difference at α44. The residues are found in and around anchor pockets 1 and 9, as potential TCR contacts, in the areas for CD4 binding and putative homodimer formation. The identification of three HLA-DQ AA (α44, β57, β135) conferring T1D risk should sharpen functional and translational studies.

Obesity is a risk factor for type 2 diabetes (T2D), however not all obese individuals develop the disease. In this study, we aimed to investigate the cause of differential insulin secretion capacity of pancreatic islets from T2D and non-T2D (ND) especially obese donors (BMI ≥30 kg/m²). Islets from obese T2D donors had reduced insulin secretion, decreased β-cell exocytosis and higher expression of fatty acid translocase CD36. We tested the hypothesis that CD36 is a key molecule in the reduced insulin secretion capacity. Indeed, CD36 overexpression led to decreased insulin secretion, impaired exocytosis and reduced granule docking. This was accompanied with reduced expression of the exocytotic proteins, SNAP25, STXBP1 and VAMP2, likely because CD36 induced down-regulation of the IRS proteins, suppressed insulin signaling PI3K-AKT pathway and increased nuclear localization of the transcription factor FoxO1. CD36 antibody treatment of the human β-cell line, EndoC-βH1, increased IRS1 and exocytotic protein levels, improved granule docking and enhanced insulin secretion. Our results demonstrate that β-cells from obese T2D donors have dysfunctional exocytosis likely due to an abnormal lipid handling represented by differential CD36 expression. Hence, CD36 could be a key molecule to limit β-cell function in T2D associated with obesity.