PtdIns(3)P plays critical roles in the autophagy pathway. However, little is known about how PtdIns(3)P effectors act with autophagy proteins in autophagosome formation. Here we identified an essential autophagy gene in C. elegans, epg-6, which encodes a WD40 repeat-containing protein with PtdIns(3)P-binding activity. EPG-6 directly interacts with ATG-2. epg-6 and atg-2 regulate progression of omegasomes to autophagosomes, and their loss of function causes accumulation of enlarged early autophagic structures. Another WD40 repeat PtdIns(3)P effector, ATG-18, plays a distinct role in autophagosome formation. We also established the hierarchical relationship of autophagy genes in degradation of protein aggregates and revealed that the UNC-51/Atg1 complex, EPG-8/Atg14, and binding of lipidated LGG-1 to protein aggregates are required for omegasome formation. Our study demonstrates that autophagic PtdIns(3)P effectors play distinct roles in autophagosome formation and also provides a framework for understanding the concerted action of autophagy genes in protein aggregate degradation.

The mechanism by which nutrient status regulates the fusion of autophagosomes with endosomes/lysosomes is poorly understood. Here, we report that O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) mediates O-GlcNAcylation of the SNARE protein SNAP-29 and regulates autophagy in a nutrient-dependent manner. In mammalian cells, OGT knockdown, or mutating the O-GlcNAc sites in SNAP-29, promotes the formation of a SNAP-29-containing SNARE complex, increases fusion between autophagosomes and endosomes/lysosomes, and promotes autophagic flux. In Caenorhabditis elegans, depletion of ogt-1 has a similar effect on autophagy; moreover, expression of an O-GlcNAc-defective SNAP-29 mutant facilitates autophagic degradation of protein aggregates. O-GlcNAcylated SNAP-29 levels are reduced during starvation in mammalian cells and in C. elegans. Our study reveals a mechanism by which O-GlcNAc-modification integrates nutrient status with autophagosome maturation.

Systemic lupus erythematosus (SLE) is a complicated autoimmune disease of multifactorial pathoaetiology. One of the most serious manifestations is lupus nephritis. The pathogenesis of SLE has not been well elucidated, but it has been reported that interleukin-17 (IL-17) and Th17 cells play important roles in the pathogenesis of SLE. IL-17A, a member of IL-17 family, amplifies the immune response by inducing the local production of chemokines and cytokines, recruiting neutrophils and monocytes, augmenting the production of autoantibodies, and aggravating the inflammation and damage of target organs such as the kidney in SLE. In recent years, several IL-17A pathway inhibitors have advanced into clinical trials, including the anti-IL-17A monoclonal antibody and the anti-17RA monoclonal antibody. Several agents have shown great success in Phase II trials in multiple autoimmune diseases such as psoriasis, rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis, and non-infectious uveitis, which has sparked the urgent need of anti-IL-17A as innovative therapeutic option in controlling disease activity of moderate-to-severe SLE. Here, we review and summarize current progress in IL-17A and SLE from in vitro studies, human expression studies, and animal models, providing novel insight into its therapeutic potential.