9c9i
Structure of the TSC1:WIPI3 complex
Structural highlights
DiseaseWIPI3_HUMAN The disease may be caused by mutations affecting the gene represented in this entry. FunctionWIPI3_HUMAN Component of the autophagy machinery that controls the major intracellular degradation process by which cytoplasmic materials are packaged into autophagosomes and delivered to lysosomes for degradation (PubMed:28561066). Binds phosphatidylinositol 3-phosphate (PtdIns3P) forming on membranes of the endoplasmic reticulum upon activation of the upstream ULK1 and PI3 kinases and is recruited at phagophore assembly sites where it regulates the elongation of nascent phagophores downstream of WIPI2 (PubMed:28561066). In the cellular response to starvation, may also function together with the TSC1-TSC2 complex and RB1CC1 in the inhibition of the mTORC1 signaling pathway (PubMed:28503735).[1] [2] Publication Abstract from PubMedTuberous sclerosis complex (TSC) is targeted to the lysosomal membrane, where it hydrolyzes RAS homolog-mTORC1 binding (RHEB) from its GTP-bound to GDP-bound state, inhibiting mechanistic target of rapamycin complex 1 (mTORC1). Loss-of-function mutations in TSC cause TSC disease, marked by excessive tumor growth. Here, we overcome a high degree of continuous conformational heterogeneity to determine the 2.8-A cryo-electron microscopy (cryo-EM) structure of the complete human TSC in complex with the lysosomal recruitment factor WD repeat domain phosphoinositide-interacting protein 3 (WIPI3). We discover a previously undetected amino-terminal TSC1 HEAT repeat dimer that clamps onto a single TSC wing and forms a phosphatidylinositol phosphate (PIP)-binding pocket, which specifically binds monophosphorylated PIPs. These structural advances provide a model by which WIPI3 and PIP-signaling networks coordinate to recruit TSC to the lysosomal membrane to inhibit mTORC1. The high-resolution TSC structure reveals previously unrecognized mutational hotspots and uncovers crucial insights into the mechanisms of TSC dysregulation in disease. Structure of the human TSC:WIPI3 lysosomal recruitment complex.,Bayly-Jones C, Lupton CJ, D'Andrea L, Chang YG, Jones GD, Steele JR, Venugopal H, Schittenhelm RB, Halls ML, Ellisdon AM Sci Adv. 2024 Nov 22;10(47):eadr5807. doi: 10.1126/sciadv.adr5807. Epub 2024 Nov , 20. PMID:39565846[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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