School bus drivers in the Upper Grand District School Board are transporting school work instead of students.

A woman in her 90s living at the Bradford Valley Care Community is the latest coronavirus victim in the region.

The Shelburne Retirement Residence has been devastated by an outbreak of COVID-19, with 90 per cent of its residents becoming infected.

An eight-year-old boy with good intentions sparked a missing person search on Tuesday.

Grey Bruce provincial police say the OPP canine unit found human remains in Meaford, and one person is under arrest.

While infection rates remain steady across the region, the Simcoe Muskoka District Health Unit is reporting more than half of all 360 cases have now recovered.

Nurses, PSWs, and front-line workers in long-term care and retirement homes have been dealing with the full reality of this pandemic every day.

With the eviction date looming for campers to leave Oppenheimer Park, B.C.'s social development minister says everyone is still expected to be out of the park by Saturday.

Vancouver resident Hugo Huynh says he's never seen the man who got out of a minivan outside his home early Monday morning and uprooted the young tree.

B.C. recorded 29 more cases of COVID-19 and one more death over the last 24 hours, provincial health officials announced Friday.

The following article, Univ of Pittsburg Researcher, China Native, Dr. Bing Liu, “On the verge” of COVID19 Breakthrough Is Murdered…Alleged Gunman, Hao Gu, Kills Himself, was first published on 100PercentFedUp.com.

A 37-year-old China native and "outstanding researcher" at the University of Pittsburgh...

Continue reading: Univ of Pittsburg Researcher, China Native, Dr. Bing Liu, “On the verge” of COVID19 Breakthrough Is Murdered…Alleged Gunman, Hao Gu, Kills Himself ...

The following article, BREAKING: CBS News Allegedly Staged Fake COVID19 Testing In MI…Makes Dem Gov Whitmer Look Like She’s Doing More To Help Citizens Than Fed Government [VIDEO], was first published on 100PercentFedUp.com.

Project Veritas founder James O’Keefe has done it again. He’s uncovered yet another deceitful piece of coverage on the Wuhan coronavirus pandemic in America by CBS News. O’Keefe begins his interview with a man whose identity is being hidden, “You’re telling me—you’re 100% certain, that CBS News, CBS News Corporation national—staged a fake event. They […]

Continue reading: BREAKING: CBS News Allegedly Staged Fake COVID19 Testing In MI…Makes Dem Gov Whitmer Look Like She’s Doing More To Help Citizens Than Fed Government [VIDEO] ...

The following article, BREAKING: Sen Marsha Blackburn Introduces Stop COVID Act…Allowing US Citizens To Sue Communist China For Damage They’ve Inflicted On Our Nation, was first published on 100PercentFedUp.com.

Yesterday, Senator Marsha Blackburn (R-TN), along with Senator Martha McSally (R-AZ) introduced the Stop COVID Act, giving Americans the ability to sue Communist China for the damage they’ve inflicted on our nation. Senator Blackburn appeared on Fox News with host Judge Jeanine where she explained the act to Jeanine Pirro. Blackburn told the Fox News […]

Continue reading: BREAKING: Sen Marsha Blackburn Introduces Stop COVID Act…Allowing US Citizens To Sue Communist China For Damage They’ve Inflicted On Our Nation ...

The following article, BREAKING: 43-Yr-Old Father Of 9, Dollar Store Sec Guard, Shot DEAD While Allegedly Trying To Enforce MI Gov Whitmer’s Face Covering Exec Order, was first published on 100PercentFedUp.com.

Will the mainstream media report about the senseless death of a 43-year-old father of nine, who would have been alive today if it were not for VP wannabe, Gretchen Whitmer's executive order that forced him to respond to a customer not wearing a face mask? 

Continue reading: BREAKING: 43-Yr-Old Father Of 9, Dollar Store Sec Guard, Shot DEAD While Allegedly Trying To Enforce MI Gov Whitmer’s Face Covering Exec Order ...

The following article, BREAKING: MI Lawmakers File Lawsuit Challenging Governor’s “Improper” and “Invalid” Emergency Orders: “We’ve attempted to partner with our governor, but she’s rejected”, was first published on 100PercentFedUp.com.

In addition to crushing Michigan's economy, the governor's reckless, one-size-fits-all executive orders are harming an untold number of Michigan citizens.

Continue reading: BREAKING: MI Lawmakers File Lawsuit Challenging Governor’s “Improper” and “Invalid” Emergency Orders: “We’ve attempted to partner with our governor, but she’s rejected” ...

The following article, NY Shame: Workers Who Tested Positive For COVID-19 Were Allowed To Remain On The Job At Nursing Homes, As Death Toll For Nursing Home Patients Exceeds 3,000, was first published on 100PercentFedUp.com.

The coronavirus crisis at New York’s nursing homes is even worse than previously thought. Monday night, the state Department of Health issued new data, adding more than 1,600 people who were presumed to have died of the virus in nursing homes, but did not have a confirmed diagnosis, to the official toll. As of May […]

Continue reading: NY Shame: Workers Who Tested Positive For COVID-19 Were Allowed To Remain On The Job At Nursing Homes, As Death Toll For Nursing Home Patients Exceeds 3,000 ...

The following article, Breaking: Texas AG Calls for Immediate Release of Salon Owner Jailed for Opening…Texas Lt Gov Offers to Pay Salon Owner’s $7k Fine, was first published on 100PercentFedUp.com.

Salon A La Mode owner Shelley Luther opened her salon in defiance of the lockdown order for salons to stay closed during the coronavirus crisis. She boldly ripped. up the citation she was given by the police and refused to shut her doors. Luther hired a lawyer and went to court where an activist judge […]

Continue reading: Breaking: Texas AG Calls for Immediate Release of Salon Owner Jailed for Opening…Texas Lt Gov Offers to Pay Salon Owner’s $7k Fine ...

The following article, Chicago Inmate Switches Identities While Wearing Mask…Is Released from Jail, was first published on 100PercentFedUp.com.

A Cook County, Chicago inmate, was able to switch identities with another inmate allowing the wrong inmate to be released. How did they carry that off without anyone catching them? The inmate was wearing a mask when he was released, so it wasn’t as easy to identify him. Last Saturday, Quintin Henderson (pictured below), 28, […]

Continue reading: Chicago Inmate Switches Identities While Wearing Mask…Is Released from Jail ...

The following article, Texas Gov Abbott Frees Salon Owner Shelley Luther: “Criminals shouldn’t be released to prevent COVID-19 just to put business owners in their place”, was first published on 100PercentFedUp.com.

Texas Governor Greg Abbott just changed the coronavirus order to free Salon A La Mode owner Shelley Luther from jail. Abbott tweeted out a comment about the poor treatment of the business owner: Throwing Texans in jail whose biz’s shut down through no fault of their own is wrong. I am eliminating jail for violating […]

Continue reading: Texas Gov Abbott Frees Salon Owner Shelley Luther: “Criminals shouldn’t be released to prevent COVID-19 just to put business owners in their place” ...

The following article, Breaking: Justice Department Dropping Michael Flynn Criminal Case, was first published on 100PercentFedUp.com.

Michael Flynn has finally been exonerated. The Associated Press is reporting exclusively that the Justice Department said it is dropping the criminal case against President Trump’s first national security adviser, Michael Flynn. In court documents being filed Thursday, the Justice Department said it is dropping the case “after a considered review of all the facts […]

Continue reading: Breaking: Justice Department Dropping Michael Flynn Criminal Case ...

The following article, Video: Salon Owner Shelley Luther Released from Jail After Obama-Loyalist Judge Sentenced Her to 7 Days, was first published on 100PercentFedUp.com.

Salon A La Mode owner Shelley Luther was just released from jail today. The Texas Supreme Court and Texas Governor Greg Abbott both called for her release today (see below). When Luther left jail she was greeted by supporters who yelled “Shelley’s Free!” She thanked all of the new friends she’s made during this difficult […]

Continue reading: Video: Salon Owner Shelley Luther Released from Jail After Obama-Loyalist Judge Sentenced Her to 7 Days ...

The following article, BREAKING: Michigan’s Radical Governor Extends Lockdown AGAIN…Only One Day After Church Leaders and MI Lawmakers File Suit Against Her, was first published on 100PercentFedUp.com.

Michigan was the first state to see protests against draconian lockdown measures by an overreaching governor. On April 15, the Michigan Conservative Coalition organized an in-vehicle protest in Lansing, MI that drew an estimated 15,000 vehicles. Since that time, several protests by Michigan workers who are being devastated by the one-size-fits-all shut down of the […]

Continue reading: BREAKING: Michigan’s Radical Governor Extends Lockdown AGAIN…Only One Day After Church Leaders and MI Lawmakers File Suit Against Her ...

The following article, Mother of the Year, Michelle Obama Explains How Having Kids Was A “Concession”… Had To Give Up Her “Aspirations and Dreams” [VIDEO], was first published on 100PercentFedUp.com.

While campaigning for her community organizer turned presidential candidate husband, Barack, Michelle Obama told a crowd of his supporters in Milwaukee, Wisconsin that for the first time in her life, she was proud to be an American. Four years later, Michelle Obama was a keynote speaker at the DNC convention, where she told Democrats how […]

Continue reading: Mother of the Year, Michelle Obama Explains How Having Kids Was A “Concession”… Had To Give Up Her “Aspirations and Dreams” [VIDEO] ...

The following article, Woman Shoots Three Teenage McDonald’s Workers For Telling Her She Couldn’t Eat In Dining Room Over COVID19 Restrictions, was first published on 100PercentFedUp.com.

An angry Oklahoma woman shot at a group of teenagers working at a local McDonald’s after they explained to her that the dining room was closed due to coronavirus restrictions. 32-year-old Gloricia Woody was arrested by the Oklahoma City Police and charged with the shooting. From the Oklahoma City Police -Last night, officers were called […]

Continue reading: Woman Shoots Three Teenage McDonald’s Workers For Telling Her She Couldn’t Eat In Dining Room Over COVID19 Restrictions ...

The following article, BREAKING: Ex-Cop Father and Son Arrested and Charged With Murder of Black Man Jogging In Neighborhood…President Trump Responds [VIDEO], was first published on 100PercentFedUp.com.

The Georgia Bureau of Investigations has arrested a father and son duo, 64-year-old ex-cop, Gregory McMichael, and his son, 34-year-old Travis McMichael for the February murder of  24-year-old Ahmaud Arbery, a black man who was jogging through their neighborhood when they jumped in their truck and pursued him. Yashar Ali shared the news of the […]

Continue reading: BREAKING: Ex-Cop Father and Son Arrested and Charged With Murder of Black Man Jogging In Neighborhood…President Trump Responds [VIDEO] ...

The following article, BREAKING: New Docs Prove Obama Knew Details Of Flynn Wiretapping…Newly Surfaced Video Shows Obama Explaining How He Stays Out Of FBI Investigations, was first published on 100PercentFedUp.com.

Barack Obama knew. Documents released yesterday that were used to exonerate President Trump’s new NSA General Flynn, prove that President Barack Obama was aware of the details of Michael Flynn’s intercepted phone calls on December 16 with then-Russian Ambassador Sergey Kislyak. On January 5, 2017, then-Deputy Attorney General, Sally Yates attended an Oval Office meeting […]

Continue reading: BREAKING: New Docs Prove Obama Knew Details Of Flynn Wiretapping…Newly Surfaced Video Shows Obama Explaining How He Stays Out Of FBI Investigations ...

The following article, BREAKING: President Trump’s Fiery Interview On Fox & Friends…”These are dirty politicians and dirty cops…They put our nation in danger with other nations, including Russia” [VIDEO], was first published on 100PercentFedUp.com.

This morning during a nearly one hour interview with Fox & Friends, President Trump addressed the decision by the DOJ to drop the case against the innocent General Michael Flynn. Trump ripped into the “dirty politicians and dirty cops” who went after General Michael Flynn. President Trump called the players involved in the horrible plot […]

Continue reading: BREAKING: President Trump’s Fiery Interview On Fox & Friends…”These are dirty politicians and dirty cops…They put our nation in danger with other nations, including Russia” [VIDEO] ...

The following article, Fed Judge Releases 21-Yr-Old Man To “Clean and Sober House” After Appearing In Court For Sexually Assaulting 12-Yr-Old Girl For One Month While Hiding In Her Bedroom, was first published on 100PercentFedUp.com.

The normalizing of pedophilia is not a far-right conspiracy theory...

Continue reading: Fed Judge Releases 21-Yr-Old Man To “Clean and Sober House” After Appearing In Court For Sexually Assaulting 12-Yr-Old Girl For One Month While Hiding In Her Bedroom ...

The following article, Greg Gutfeld Levels Ilhan Omar With Epic Response To Her Claim That “White Privilege” Is Reason Charges Were Dropped Against General Flynn, was first published on 100PercentFedUp.com.

Yesterday, after 3 1/2 years of having his character and integrity called into question, President Trump's first NSA, General Michael Flynn was finally...

Continue reading: Greg Gutfeld Levels Ilhan Omar With Epic Response To Her Claim That “White Privilege” Is Reason Charges Were Dropped Against General Flynn ...

The following article, BREAKING: Vice President Mike Pence’s Press Sec Katie Miller, Wife of President Trump’s Sr. Advisor, Stephen Miller, Tests Positive For COVID-19, was first published on 100PercentFedUp.com.

Only moments ago, White House Press Secretary Kayleigh McEnany confirmed that a member of Vice President Mike Pence’s team tested positive for coronavirus. Watch: White House Press Secretary Kayleigh McEnany confirms a member of Vice President Mike Pence's team tested positive for coronavirus pic.twitter.com/3VaUXbwMq7 — Bloomberg QuickTake (@QuickTake) May 8, 2020 Reuters White House Correspondent […]

Continue reading: BREAKING: Vice President Mike Pence’s Press Sec Katie Miller, Wife of President Trump’s Sr. Advisor, Stephen Miller, Tests Positive For COVID-19 ...

The following article, Obama Private Call Released: Implores Political Operatives to Help Protect Him…”We gotta make this happen”, was first published on 100PercentFedUp.com.

Michael Isikoff at Yahoo News on Friday night released audio of a call from former President Barack Obama to political operatives and the media to help protect “the rule of law” by protecting him. Obama desperately wants the Deep State and media to protect him by helping elect Joe Biden: “The fact that there is […]

Continue reading: Obama Private Call Released: Implores Political Operatives to Help Protect Him…”We gotta make this happen” ...

After being pulled over for what started as a traffic violation, two Windsor men were arrested and face multiple drug, property, and weapon related charges.

Essex County OPP have released a composite drawing of a suspect reported to be impersonating a police officer in Lakeshore.

One more person has died from the coronavirus in the Windsor-Essex region on Saturday and nine new cases have been reported by the health unit.

Health officials with the Manitoba government announced on Friday that a COVID-19 outbreak at the Health Sciences Centre has officially been declared over.

A beverage company in the U.S. is inviting moms to let out a ‘quaranscream’ this Mother’s Day on a designated ‘zero-judgement venting hotline’ for a chance to win its wine spritzers.

Environment Canada has issued a special weather statement for the southwestern area of Manitoba.

Little Richard, the self-proclaimed "architect of rock 'n' roll" whose piercing wail, pounding piano and towering pompadour irrevocably altered popular music while introducing black R&B to white America, has died Saturday. He was 87.

Manitoba’s unemployment rate nearly doubled between March and April, according to the monthly report from Statistics Canada released Friday morning.

10 October 2019

This paper examines the governance problems in the monetary system and global trade and regulation. It then explores whether issues have arisen because the US has given up its dominant role, and if so how these might be rectified.

27 April 2020

Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4.

Previous studies have shown that sphingosine kinase interacting protein (SKIP) inhibits sphingosine kinase (SK) function in fibroblasts. SK phosphorylates sphingosine producing the potent signaling molecule sphingosine-1-phosphate (S1P). SKIP gene (SPHKAP) expression is silenced by hypermethylation of its promoter in acute myeloid leukemia (AML). However, why SKIP activity is silenced in primary AML cells is unclear. Here, we investigated the consequences of SKIP down-regulation in AML primary cells and the effects of SKIP re-expression in leukemic cell lines. Using targeted ultra-HPLC-tandem MS (UPLC-MS/MS), we measured sphingolipids (including S1P and ceramides) in AML and control cells. Primary AML cells had significantly lower SK activity and intracellular S1P concentrations than control cells, and SKIP-transfected leukemia cell lines exhibited increased SK activity. These findings show that SKIP re-expression enhances SK activity in leukemia cells. Furthermore, other bioactive sphingolipids such as ceramide were also down-regulated in primary AML cells. Of note, SKIP re-expression in leukemia cells increased ceramide levels 2-fold, inactivated the key signaling protein extracellular signal-regulated kinase, and increased apoptosis following serum deprivation or chemotherapy. These results indicate that SKIP down-regulation in AML reduces SK activity and ceramide levels, an effect that ultimately inhibits apoptosis in leukemia cells. The findings of our study contrast with previous results indicating that SKIP inhibits SK function in fibroblasts and therefore challenge the notion that SKIP always inhibits SK activity.

The transcription factor forkhead box P3 (FOXP3) is a biomarker for regulatory T cells and can also be expressed in cancer cells, but its function in cancer appears to be divergent. The role of hepatocyte-expressed FOXP3 in hepatocellular carcinoma (HCC) is unknown. Here, we collected tumor samples and clinical information from 115 HCC patients and used five human cancer cell lines. We examined FOXP3 mRNA sequences for mutations, used a luciferase assay to assess promoter activities of FOXP3's target genes, and employed mouse tumor models to confirm in vitro results. We detected mutations in the FKH domain of FOXP3 mRNAs in 33% of the HCC tumor tissues, but in none of the adjacent nontumor tissues. None of the mutations occurred at high frequency, indicating that they occurred randomly. Notably, the mutations were not detected in the corresponding regions of FOXP3 genomic DNA, and many of them resulted in amino acid substitutions in the FKH region, altering FOXP3's subcellular localization. FOXP3 delocalization from the nucleus to the cytoplasm caused loss of transcriptional regulation of its target genes, inactivated its tumor-inhibitory capability, and changed cellular responses to histone deacetylase (HDAC) inhibitors. More complex FKH mutations appeared to be associated with worse prognosis in HCC patients. We conclude that mutations in the FKH domain of FOXP3 mRNA frequently occur in HCC and that these mutations are caused by errors in transcription and are not derived from genomic DNA mutations. Our results suggest that transcriptional mutagenesis of FOXP3 plays a role in HCC.

Prostate cancer (PCa) cells heavily rely on an active androgen receptor (AR) pathway for their survival. Enzalutamide (MDV3100) is a second-generation antiandrogenic drug that was approved by the Food and Drug Administration in 2012 to treat patients with castration-resistant prostate cancer (CRPC). However, emergence of resistance against this drug is inevitable, and it has been a major challenge to develop interventions that help manage enzalutamide-resistant CRPC. Erythropoietin-producing human hepatocellular (Eph) receptors are targeted by ephrin protein ligands and have a broad range of functions. Increasing evidence indicates that this signaling pathway plays an important role in tumorigenesis. Overexpression of EPH receptor B4 (EPHB4) has been observed in multiple types of cancer, being closely associated with proliferation, invasion, and metastasis of tumors. Here, using RNA-Seq analyses of clinical and preclinical samples, along with several biochemical and molecular methods, we report that enzalutamide-resistant PCa requires an active EPHB4 pathway that supports drug resistance of this tumor type. Using a small kinase inhibitor and RNAi-based gene silencing to disrupt EPHB4 activity, we found that these disruptions re-sensitize enzalutamide-resistant PCa to the drug both in vitro and in vivo. Mechanistically, we found that EPHB4 stimulates the AR by inducing proto-oncogene c-Myc (c-Myc) expression. Taken together, these results provide critical insight into the mechanism of enzalutamide resistance in PCa, potentially offering a therapeutic avenue for enhancing the efficacy of enzalutamide to better manage this common malignancy.

Heterotrimeric G proteins are the core upstream elements that transduce and amplify the cellular signals from G protein–coupled receptors (GPCRs) to intracellular effectors. GPCRs are the largest family of membrane proteins encoded in the human genome and are the targets of about one-third of prescription medicines. However, to date, no single therapeutic agent exerts its effects via perturbing heterotrimeric G protein function, despite a plethora of evidence linking G protein malfunction to human disease. Several recent studies have brought to light that the Gq family–specific inhibitor FR900359 (FR) is unexpectedly efficacious in silencing the signaling of Gq oncoproteins, mutant Gq variants that mostly exist in the active state. These data not only raise the hope that researchers working in drug discovery may be able to potentially strike Gq oncoproteins from the list of undruggable targets, but also raise questions as to how FR achieves its therapeutic effect. Here, we place emphasis on these recent studies and explain why they expand our pharmacological armamentarium for targeting Gq protein oncogenes as well as broaden our mechanistic understanding of Gq protein oncogene function. We also highlight how this novel insight impacts the significance and utility of using G(q) proteins as targets in drug discovery efforts.

The Mycobacterium tuberculosis virulence factor EsxA and its chaperone EsxB are secreted as a heterodimer (EsxA:B) and are crucial for mycobacterial escape from phagosomes and cytosolic translocation. Current findings support the idea that for EsxA to interact with host membranes, EsxA must dissociate from EsxB at low pH. However, the molecular mechanism by which the EsxA:B heterodimer separates is not clear. In the present study, using liposome-leakage and cytotoxicity assays, LC-MS/MS–based proteomics, and CCF-4 FRET analysis, we obtained evidence that the Nα-acetylation of the Thr-2 residue on EsxA, a post-translational modification that is present in mycobacteria but absent in Escherichia coli, is required for the EsxA:B separation. Substitutions at Thr-2 that precluded Nα-acetylation inhibited the heterodimer separation and hence prevented EsxA from interacting with the host membrane, resulting in attenuated mycobacterial cytosolic translocation and virulence. Molecular dynamics simulations revealed that at low pH, the Nα-acetylated Thr-2 makes direct and frequent “bind-and-release” contacts with EsxB, which generates a force that pulls EsxB away from EsxA. In summary, our findings provide evidence that the Nα-acetylation at Thr-2 of EsxA facilitates dissociation of the EsxA:B heterodimer required for EsxA membrane permeabilization and mycobacterial cytosolic translocation and virulence.

Type 2 diabetes mellitus (T2DM) is characterized by impaired glucose-stimulated insulin secretion and increased peripheral insulin resistance. Unremitting endoplasmic reticulum (ER) stress can lead to beta-cell apoptosis and has been linked to type 2 diabetes. Although many studies have attempted to link ER stress and T2DM, the specific effects of ER stress on beta-cell function remain incompletely understood. To determine the interrelationship between ER stress and beta-cell function, here we treated insulin-secreting INS-1(832/13) cells or isolated mouse islets with the ER stress–inducer tunicamycin (TM). TM induced ER stress as expected, as evidenced by activation of the unfolded protein response. Beta cells treated with TM also exhibited concomitant alterations in their electrical activity and cytosolic free Ca2+ oscillations. As ER stress is known to reduce ER Ca2+ levels, we tested the hypothesis that the observed increase in Ca2+ oscillations occurred because of reduced ER Ca2+ levels and, in turn, increased store-operated Ca2+ entry. TM-induced cytosolic Ca2+ and membrane electrical oscillations were acutely inhibited by YM58483, which blocks store-operated Ca2+ channels. Significantly, TM-treated cells secreted increased insulin under conditions normally associated with only minimal release, e.g. 5 mm glucose, and YM58483 blocked this secretion. Taken together, these results support a critical role for ER Ca2+ depletion–activated Ca2+ current in mediating Ca2+-induced insulin secretion in response to ER stress.

Bacterial type VII secretion systems secrete a wide range of extracellular proteins that play important roles in bacterial viability and in interactions of pathogenic mycobacteria with their hosts. Mycobacterial type VII secretion systems consist of five subtypes, ESX-1–5, and have four substrate classes, namely, Esx, PE, PPE, and Esp proteins. At least some of these substrates are secreted as heterodimers. Each ESX system mediates the secretion of a specific set of Esx, PE, and PPE proteins, raising the question of how these substrates are recognized in a system-specific fashion. For the PE/PPE heterodimers, it has been shown that they interact with their cognate EspG chaperone and that this chaperone determines the designated secretion pathway. However, both structural and pulldown analyses have suggested that EspG cannot interact with the Esx proteins. Therefore, the determining factor for system specificity of the Esx proteins remains unknown. Here, we investigated the secretion specificity of the ESX-1 substrate pair EsxB_1/EsxA_1 in Mycobacterium marinum. Although this substrate pair was hardly secreted when homologously expressed, it was secreted when co-expressed together with the PE35/PPE68_1 pair, indicating that this pair could stimulate secretion of the EsxB_1/EsxA_1 pair. Surprisingly, co-expression of EsxB_1/EsxA_1 with a modified PE35/PPE68_1 version that carried the EspG5 chaperone-binding domain, previously shown to redirect this substrate pair to the ESX-5 system, also resulted in redirection and co-secretion of the Esx pair via ESX-5. Our results suggest a secretion model in which PE35/PPE68_1 determines the system-specific secretion of EsxB_1/EsxA_1.