WASH regulates endosomal sorting, but its roles are ill defined. WASH-knockout MEFs display enlarged yet ordered endosomes without aberrant tubulation and a collapsed lysosomal network. Without WASH, EGFR is basally degraded, whereas TfnR is not, which supports discrete receptor trafficking via WASH-dependent and WASH-independent mechanisms.

Macroautophagy is an evolutionarily conserved cellular process involved in the clearance of proteins and organelles. Although the cytoplasmic machinery that orchestrates autophagy induction during starvation, hypoxia, or receptor stimulation has been widely studied, the key epigenetic events that initiate and maintain the autophagy process remain unknown. Here we show that the methyltransferase G9a coordinates the transcriptional activation of key regulators of autophagosome formation by remodeling the chromatin landscape. Pharmacological inhibition or RNA interference (RNAi)-mediated suppression of G9a induces LC3B expression and lipidation that is dependent on RNA synthesis, protein translation, and the methyltransferase activity of G9a. Under normal conditions, G9a associates with the LC3B, WIPI1, and DOR gene promoters, epigenetically repressing them. However, G9a and G9a-repressive histone marks are removed during starvation and receptor-stimulated activation of naive T cells, two physiological inducers of macroautophagy. Moreover, we show that the c-Jun N-terminal kinase (JNK) pathway is involved in the regulation of autophagy gene expression during naive-T-cell activation. Together, these findings reveal that G9a directly represses genes known to participate in the autophagic process and that inhibition of G9a-mediated epigenetic repression represents an important regulatory mechanism during autophagy.A utophagy is an evolutionarily conserved catabolic process in eukaryotes that involves lysosomal degradation of cellular components, including long-lived proteins and organelles. There are four main forms of autophagy: macroautophagy (referred to here as autophagy), selective autophagy, microautophagy, and chaperone-mediated autophagy (1-4). Autophagy serves as an adaptive response to protect cells or organisms during periods of cellular stress, such as nutrient deprivation. In addition, autophagy can participate in several cellular and developmental processes, including homeostasis, clearance of intracellular pathogens, and immunity (1). Due to its fundamental importance for cellular survival, autophagy regulation has been implicated in several human diseases, such as cancer and neurodegenerative disorders (2, 5).Autophagy initiation involves the de novo synthesis of a double-membrane structure known as the phagophore, which ultimately elongates and closes to sequester cytoplasmic proteins and organelles, forming the autophagosome. The autophagosome subsequently undergoes a stepwise maturation process that culminates in its fusion with acidified endosomal/lysosomal vesicles, resulting in the degradation of its contents into useful biomolecules (2). A screen of yeast mutants unable to survive under nitrogen deprivation characterized a network of autophagy-related (ATG) genes (6). Mammalian homologues of these ATGs were later identified and shown to participate during distinct steps of autophagy. For example, microtubule-associated protein light chain 3 (LC3B) undergoes lipidation and is recruited to the pha...

The single nucleotide polymorphism, rs1990760, in the cytosolic viral sensor, IFIH1, results in an amino-acid change (p.A946T) and is associated with multiple autoimmune diseases. The impact of this polymorphism on both viral-sensing and autoimmune pathogenesis remains poorly understood. Here, we find that human PBMCs and cell lines with the risk variant, IFIH1T946, exhibit heightened, basal and ligand-triggered type I interferon (IFN-I) production. Consistent with these findings, IFIH1T946 knock-in mice display enhanced basal IFN-I expression, survive a lethal viral challenge, and exhibit increased penetrance in autoimmune models including a combinatorial impact with other risk variants. Further, IFIH1T946 mice manifest an embryonic survival defect consistent with enhanced responsiveness to RNA self-ligands. Together, our data support a model wherein autoimmune risk variant-driven, ligand-triggered IFN-I production functions to protect against viral challenge, likely accounting for its selection within human populations, but provides this advantage at the cost of modestly promoting the risk for autoimmunity.

Understanding angiogenesis and growth control is central for elucidating prostate tumorigenesis. However, the mechanisms of activation of the angiogenic gene, vascular endothelial growth factor (VEGF) are complex and its regulation in prostate cancer is not well understood. In previous studies, VEGF expression levels were correlated with altered levels of the zinc finger transcription factor, WTl. Since the VEGF promoter has several potential WTl binding sites and WT1 regulates many growth control genes, here we assessed whether WTl might also regulate VEGF transcription. Using transfection and DNA binding assays, functional WTl binding sites were localized within the proximal VEGF promoter. Transfection of the DDS-WTl (R394W) zinc finger mutant had no significant effect on VEGF-luciferase reporter activity, suggesting that an intact zinc finger DNA binding domain was required. Interestingly, WTl-mediated regulation of VEGF reporter constructs varied in different cell types. In androgen-responsive, LNCaP prostate cancer cells, hormone treatment enhanced WTl-mediated activation of the VEGF promoter constructs. Overall, these results suggest that WTl transcriptionally regulates VEGF through interaction of its zinc finger DNA binding domain with the proximal GC-rich VEGF promoter. These findings may shed light on the role of WTl in angiogenesis and prostate cancer progression.