Duttke, S. | Search bioRxiv

bioRxiv2022

Derlin Dfm1 Employs a Chaperone Function to Resolve Misfolded Membrane Protein Stress

Accumulation of misfolded proteins is a known source of cellular stress and can be detrimental to cellular health. While protein aggregation is a known hallmark of many diseases, the mechanisms by which protein aggregates cause toxicity and the molecular machines that prevent this toxicity are not completely understood. Here, we show that the accumulated misfolded membrane proteins form endoplasmic reticulum (ER) localized aggregates, impacting ubiquitin and proteasome homeostasis. Additionally, we have identified a chaperone ability of the yeast rhomboid pseudoprotease Dfm1 to influence solubilization of misfolded membrane proteins and prevent toxicity from misfolded membrane proteins. We establish that this function of Dfm1 does not require recruitment of the ATPase Cdc48 and it is distinct from Dfm1s previously identified function in dislocating misfolded membrane proteins to the cytosol for degradation.

cell biology↗

bioRxiv2022

GR-regulated enhancers play a central role in the gene regulatory networks underlying drug addiction

Substance abuse and addiction represent a significant public health problem that impacts multiple dimensions of society, including healthcare, the economy, and the workforce. In 2021, over 100,000 drug overdose deaths were reported in the US, with an alarming increase in fatalities related to opioids and psychostimulants. Understanding the fundamental gene regulatory mechanisms underlying addiction and related behaviors could facilitate more effective treatments. To explore how repeated drug exposure alters gene regulatory networks in the brain, we combined capped small (cs)RNA-seq, which accurately captures nascent-like initiating transcripts from total RNA, with Hi-C and single nuclei (sn)ATAC-seq. We profiled initiating transcripts in two addiction-related brain regions, the prefrontal cortex (PFC) and the nucleus accumbens (NAc), from rats that were never exposed to drugs or were subjected to prolonged abstinence after oxycodone or cocaine intravenous self-administration (IVSA). Interrogating over 100,000 active transcription start regions (TSRs) revealed that most TSRs had hallmarks of bonafide enhancers and highlighted the KLF/SP1, RFX, and AP1 transcription factors families as central to establishing brain-specific gene regulatory programs. Analysis of rats with addiction-like behaviors versus controls identified addiction-associated repression of transcription at regulatory enhancers recognized by nuclear receptor subfamily 3 group C (NR3C) factors, which include glucocorticoid receptors. Cell-type deconvolution analysis using snATAC-seq uncovered a potential role of glial cells in driving the gene regulatory programs associated with addiction-related phenotypes. These findings highlight the power of advanced transcriptomics methods to provide insight into how addiction perturbs gene regulatory programs in the brain.

neuroscience↗