SLC33A1/AT-1 protein regulates the induction of autophagy downstream of IRE1/XBP1 pathway.

One of the main functions of the unfolded protein response is to ensure disposal of large protein aggregates that accumulate in the lumen of the endoplasmic reticulum (ER) whereas avoiding, at least under nonlethal levels of ER stress, cell death. When tightly controlled, autophagy-dependent ER-associated degradation (ERAD(II)) allows the cell to recover from the transient accumulation of protein aggregates; however, when unchecked, it can be detrimental and cause autophagic cell death/type 2 cell death. Here we show that IRE1/XBP1 controls the induction of autophagy/ERAD(II) during the unfolded protein response by activating the ER membrane transporter SLC33A1/AT-1, which ensures continuous supply of acetyl-CoA into the lumen of the ER. Failure to induce AT-1 leads to widespread autophagic cell death. Mechanistically, the regulation of the autophagic process involves N(ε)-lysine acetylation of Atg9A.

Pride Medical at Capitol Hill: A New Lesbian, Gay, Bisexual, Transgender, Queer/Questioning plus (LGBTQ+) Patient Care Option at Kaiser Permanente Mid-Atlantic States.

When accessing medical care, lesbian, gay, bisexual, transgender, queer/questioning plus (LGBTQ+) individuals face many known challenges, including stigma, discrimination, and health disparities. Transgender and nonbinary individuals often encounter physicians and staff who are not knowledgeable about gender-affirming services and the transition journey. Finding an affirming physician can be a trial-and-error process, causing concern and uncertainty. In 2021, Kaiser Permanente Mid-Atlantic States (KPMAS) researchers published a study examining the gaps in care and experience for transgender and nonbinary patients within the KPMAS healthcare system. KPMAS realized an opportunity to both close the gaps in care identified by transgender and nonbinary patients and enhance services for the broader LGBTQ+ patient community by creating Pride Medical at Capitol Hill-an additional and optional care site for individuals who identify as LGBTQ+. During the analysis timeframe of 30 June 2021 through 30 November 2022, 586 patients accessed care through 763 visits. A total of 675 visits (88%) were for primary care and 88 (12%) for OB/GYN. Over 50% (n = 384) of total visits were conducted virtually. The plurality of patients seen identified as a man (35%; n = 204) and gay (30%; n = 176). Postvisit survey results showed that 92% of survey respondents strongly agreed that the physician treated them with courtesy and respect, and 72% of survey respondents rated their overall care as excellent. Survey results show high acceptability of this program among the patients served. Pride Medical does not carve out care. The program offers patients access to a more specialized team of physicians-a similar model to other specialties-that is easily found by the division name Pride Medical. Layering additional specialty divisions on top of existing care, for interested patients, could be an option for other medical groups and health systems seeking to offer additional options of care for interested LGBTQ+ patients.

Human-Centered Design Study to Inform Traceback Cascade Genetic Testing Programs at Three Integrated Health Systems.

INTRODUCTION: A traceback genetic testing program for ovarian cancer has the potential to identify individuals with hereditary breast and ovarian cancer and their relatives. Successful implementation depends on understanding and addressing the experiences, barriers, and preferences of the people served. METHODS: We conducted a remote, human-centered design research study of people with ovarian, fallopian tube, or peritoneal cancer (probands) and people with a family history of ovarian cancer (relatives) at three integrated health systems between May and September 2021. Participants completed activities to elicit their preferences about ovarian cancer genetic testing messaging and to design their ideal experience receiving an invitation to participate in genetic testing. Interview data were analyzed using a rapid thematic analysis approach. RESULTS: We interviewed 70 participants and identified five preferred experiences for a traceback program. Participants strongly prefer discussing genetic testing with their doctor but are comfortable discussing with other clinicians. The most highly preferred experience for both probands and relatives was to discuss with a knowledgeable clinician who could answer questions, followed by directed (sent directly to specific people) or passive (shared in a public area) communication. Repeated contact was acceptable for reminders. CONCLUSION: Participants were open to receiving information about traceback genetic testing and recognized its value. Participants preferred discussing genetic testing with a trusted clinician. Directed communication was preferable to passive communication. Other valued information included how genetic tests help their family and the cost of genetic testing. These findings are informing traceback cascade genetic testing programs at all three sites.

AT-1 is the ER membrane acetyl-CoA transporter and is essential for cell viability.

The transient or permanent modification of nascent proteins in the early secretory pathway is an essential cellular function that ensures correct folding and maturation of membrane and secreted proteins. We have recently described a new form of post-translational regulation of the membrane protein ß-site APP cleaving enzyme 1 (BACE1) involving transient lysine acetylation in the lumen of the endoplasmic reticulum (ER). The essential components of this process are two ER-based acetyl-CoA:lysine acetyltransferases, ATase1 and ATase2, and a membrane transporter that translocates acetyl-CoA into the lumen of the ER. Here, we report the functional identification of acetyl-CoA transporter 1 (AT-1) as the ER membrane acetyl-CoA transporter. We show that AT-1 regulates the acetylation status of ER-transiting proteins, including the membrane proteins BACE1, low-density lipoprotein receptor and amyloid precursor protein (APP). Finally, we show that AT-1 is essential for cell viability as its downregulation results in widespread cell death and induction of features characteristic of autophagy.

A Comprehensive Coordinator Supported Hepatitis C Virus Testing and Linkage to Treatment Program at Kaiser Permanente Mid-Atlantic States.

Since 2020, the US Preventive Services Taskforce has recommended expanding hepatitis C virus (HCV) screening to include ages 18-79, in addition to baby boomers (born 1945-1965) and those at-risk for hepatitis C virus. This retrospective cohort analysis compared patients (18 years and above) tested for HCV through usual care versus a coordinator-supported program (HCV pathway) during 2015-2018 within Kaiser Permanente Mid-Atlantic States (KPMAS). In total, 131,176 patients were tested through the HCV pathway and 128,311 through usual care (non-standardized testing). Of those tested, 1.6% (HCV pathway) and 0.5% (usual care) had chronic HCV. Of those with chronic HCV, more patients tested within the HCV pathway completed hepatic transient elastography (82.6% HCV pathway vs. 45.6% usual care; p < 0.001) and a gastroenterology visit (72.2% HCV pathway vs. 46.5% usual care; p < 0.001), and had filled prescriptions for treatment (56.5% HCV pathway vs. 40.3% usual care; p < 0.001). The median time to complete each step was shorter for those tested through the HCV pathway (hepatic transient elastography (26 vs. 118 days), gastroenterology visit (63 vs. 131 days), and prescription fill (222 vs. 326 days)). More patients tested through a coordinator-supported, standardized testing pathway completed the necessary testing steps, in less time, compared to usual care. These findings may inform institutions seeking to create effective population-wide testing programs for HCV and other conditions.

PCSK9 is required for the disposal of non-acetylated intermediates of the nascent membrane protein BACE1.

We have recently identified a new form of post-translational regulation of BACE1 (beta-site amyloid precursor protein (APP)-cleaving enzyme 1), a membrane protein that acts as the rate-limiting enzyme in the generation of the Alzheimer disease amyloid beta-peptide (Abeta). Specifically, BACE1 is transiently acetylated on seven lysine residues in the lumen of the endoplasmic reticulum/endoplasmic reticulum-Golgi intermediate compartment (ER/ERGIC). The acetylated intermediates of the nascent protein are able to reach the Golgi apparatus, whereas the non-acetylated ones are retained and degraded in a post-ER compartment. Here, we report that the serine protease PCSK9 (proprotein convertase subtilisin kexin type 9) contributes to the disposal of non-acetylated BACE1. Both overexpression and small interfering RNA-mediated downregulation of PCSK9 affected the levels of BACE1. The downregulation of PCSK9 affected the levels of the loss-of-acetylation mutants (BACE1(Ala) and BACE1(Arg)) but not those of the gain-of-acetylation mutant (BACE1(Gln)). In addition, Pcsk9(-/-) mice showed increased levels of BACE1 and Abeta in the brain. Finally, we found that nascent low-density lipoprotein receptor, a known substrate of PCSK9, is also acetylated.

A reversible form of lysine acetylation in the ER and Golgi lumen controls the molecular stabilization of BACE1.

The lipid second messenger ceramide regulates the rate of beta cleavage of the Alzheimer's disease APP (amyloid precursor protein) by affecting the molecular stability of the beta secretase BACE1 (beta-site APP cleaving enzyme 1). Such an event is stimulated in the brain by the normal process of aging, and is under the control of the general aging programme mediated by the insulin-like growth factor 1 receptor. In the present study we report that BACE1 is acetylated on seven lysine residues of the N-terminal portion of the nascent protein. This process involves lysine acetylation in the lumen of the ER (endoplasmic reticulum) and is followed by deacetylation in the lumen of the Golgi apparatus, once the protein is fully mature. We also show that specific enzymatic activities acetylate (in the ER) and deacetylate (in the Golgi apparatus) the lysine residues. This process requires carrier-mediated translocation of acetyl-CoA into the ER lumen and is stimulated by ceramide. Site-directed mutagenesis indicates that lysine acetylation is necessary for nascent BACE1 to leave the ER and move ahead in the secretory pathway, and for the molecular stabilization of the protein.