Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The endoplasmic reticulum (ER) is the site of biogenesis of the isolation membrane (IM, autophagosome precursor) and forms extensive contacts with IMs during their expansion into double-membrane autophagosomes. Little is known about the molecular mechanism underlying the formation and/or maintenance of the ER/IM contact. The integral ER proteins VAPA and VAPB (VAPs) participate in establishing ER contacts with multiple membranes by interacting with different tethers. Here, we demonstrate that VAPs also modulate ER/IM contact formation. Depletion of VAPs impairs progression of IMs into autophagosomes. Upon autophagy induction, VAPs are recruited to autophagosome formation sites on the ER, a process mediated by their interactions with FIP200 and PI(3)P. VAPs directly interact with FIP200 and ULK1 through their conserved FFAT motifs and stabilize the ULK1/FIP200 complex at the autophagosome formation sites on the ER. The formation of ULK1 puncta is significantly reduced by VAPA/B depletion. VAPs also interact with WIPI2 and enhance the formation of the WIPI2/FIP200 ER/IM tethering complex. Depletion of VMP1, which increases the ER/IM contact, greatly elevates the interaction of VAPs with these autophagy proteins. The VAPB P56S mutation, which is associated with amyotrophic lateral sclerosis, reduces the ULK1/FIP200 interaction and impairs autophagy at an early step, similar to the effect seen in VAPA/B-depleted cells. Our study reveals that VAPs directly interact with multiple ATG proteins, thereby contributing to ER/IM contact formation for autophagosome biogenesis.
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PMID:The ER Contact Proteins VAPA/B Interact with Multiple Autophagy Proteins to Modulate Autophagosome Biogenesis. 2968 7

Macroautophagy/autophagy is implicated in age-dependent neurodegenerative diseases, including amyotrophic lateral sclerosis and Parkinson, Huntington and Alzheimer diseases, suggesting that an age-related decline in neuronal autophagy may contribute to the onset of neurodegeneration. We identified a significant decline in the rate of axonal autophagosome formation in neurons cultured from aged mice, accompanied by a striking increase in the accumulation of autophagic structures with aberrant morphologies. Using live-cell microscopy, we identified the specific step in autophagosome formation that becomes impaired with age, focusing on the role of the phosphoinositide binding protein WIPI2. We determined that the dynamic and local phosphorylation of WIPI2 is a critical regulatory step in autophagosome biogenesis in neurons and that this step is specifically affected by aging. Together, these results provide new insights into the regulation of autophagosome biogenesis in neurons and delineate how autophagosome formation is affected by age. These observations also point to a potential new target for therapeutic intervention.
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PMID:Neuronal autophagy declines substantially with age and is rescued by overexpression of WIPI2. 3179 36