Quantitative proteomics in G1 cells reveals the insulin receptor adaptor IRS2 as an APC/CCdh1 substrate

ABSTRACT: The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase that controls progression through the eukaryotic cell cycle by targeting key substrates for degradation through the ubiquitin proteasome pathway. During G1, the APC/C works in concert with its co-activator Cdh1 to recognize and ubiquitinate specific substrates during this phase of the cell cycle. While many APC/CCdh1 substrates play a role cell cycle regulation, others are involved in distinct cellular processes, indicating that diverse biological pathways are subject to APC/C-mediated control. To identify novel pathways and substrates regulated by APC/CCdh1, we conducted an unbiased proteomic screen in G1-arrested RPE1 cells acutely treated with small molecule APC/C inhibitors. Combining these results with degron prediction analysis, we discovered a range of putative APC/C substrates. We validated IRS2, a key adaptor protein involved in signaling downstream of the insulin and IGF1 receptors, as a novel direct APC/CCdh1 target. We demonstrate that genetic deletion of IRS2 reduces the expression of proteins involved in cell division and functionally impairs the spindle assembly checkpoint. Together, these findings reveal a novel connection between the insulin/IGF1 signaling network and the cell cycle regulatory machinery.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Retinal Pigment Epithelial Cell, Cell Culture

SUBMITTER: Qing Yu  

LAB HEAD: Steven P Gygi

PROVIDER: PXD018329 | Pride | 2020-06-22

REPOSITORIES: Pride