Suppression of autophagy during mitosis via CUL4-RING ubiquitin ligases-mediated WIPI2 polyubiquitination and proteasomal degradation

Abstract

Macroautophagy/autophagy is a cellular process in which cytosolic contents are degraded by lysosome in response to various stress conditions. Apart from its role in the maintenance of cellular homeostasis, autophagy also involves in regulation of cell cycle progression under nutrient-deprivation conditions. However, whether and how autophagy is regulated by the cell cycle especially during mitosis remains largely undefined. Here we show that WIPI2/ATG18B (WD repeat domain, phosphoinositide interacting 2), an autophagy-related (ATG) protein that plays a critical role in autophagosome biogenesis, is a direct substrate of CUL4-RING ubiquitin ligases (CRL4s). Upon mitosis induction, CRL4s are activated via neddylation, and recruit WIPI2 via DDB1 (damage specific DNA binding protein 1), leading to polyubiquitination and proteasomal degradation of WIPI2 and suppression of autophagy. The WIPI2 protein level and autophagy during mitosis could be rescued by knockdown of CRL4s or treatment with MLN4924/Pevonedistat, a selective inhibitor of CRLs, via suppression of NAE1 (NEDD8 activating enzyme E1 subunit 1). Moreover, restoration of WIPI2 rescues autophagy during mitosis and leads to mitotic slippage and cell senescence. Our study thus discovers a novel function of CRL4s in autophagy by targeting WIPI2 for polyubiquitination and proteasomal degradation during mitosis.Abbreviations: ACTB, actin beta; ATG, autophagy-related; AMPK, AMP-activated protein kinase; AURKB/ ARK2, aurora kinase B; BafA1, bafilomycin A 1 ; CCNB1, cyclin B1; CDK1, cyclin dependent kinase 1; CHX, cycloheximide; CQ, chloroquine; CRL4s, CUL4-RING ubiquitin ligases; DDB1, damage specific DNA binding protein 1; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFP, green fluorescent protein; GST, glutathione S-transferase; MAP1LC3B/LC3B, microtubule associated protein 1 light chain 3 beta; STK11/ LKB1,serine/threonine kinase 11; MTORC1/MTOR complex 1, mechanistic target of rapamycin kinase complex 1; NAE1, NEDD8 activating enzyme E1 subunit 1; NOC, nocodazole; RING, really interesting new gene; RBX1, ring-box 1; SA-GLB1/β-gal, senescence-associated galactosidase beta 1; TSC2, TSC complex subunit 2; TUBA, tubulin alpha; WIPI2, WD repeat domain, phosphoinositide interacting 2 ARTICLE HISTORY

Ubiquitin ligase CHAF1B induces cisplatin resistance in lung adenocarcinoma by promoting NCOR2 degradation

“…Ubiquitin ligase MKRN1 regulates translating ribosome by recognizing, binding and promoting ubiquitination of its substrate PABPC1 [11]. Ubiquitin ligase Speckle-type BTB-POZ protein (SPOP) limits inflammation by promoting ubiquitination of the innate signal transducer, myeloid differentiation primary response protein 88 (MYD88) [12].During mitosis induction, ubiquitin ligase CUL4-RING (CRL4s) raises the direct substrate WIPI2/ ATG18B (WD repeat domain, phosphoinositide interacting 2), an autophagy-related (ATG) protein that plays a critical role in autophagosome biogenesis through DDB1 (damage specific DNA binding protein 1), thus leading to the polyubiquitination and proteasome degradation of WIPI2 and inhibiting autophagy [13]. It has been proved that many of ubiquitin ligases are closely related to tumor development, malignant phenotype, and cisplatin resistance in cancer [14].…”

Bioinformatics analysis and verification of gene targets for benign tracheal stenosis

“…Knockout of the CCNB1 gene could inhibit cell proliferation (Li et al, 2019), suggesting that CCNB1 could regulate cell cycle and affect cell proliferation. Furthermore, CCNB1 is involved in regulating autophagy (Lu et al, 2019), which in turn regulates the degree of tissue fibrosis (Qin et al, 2017). Apoptosis of tracheal epithelial cells can promote the proliferation of fibroblasts, thereby aggravating TS (Wang et al, 2016).…”

The Roles of Ubiquitin in Mediating Autophagy

“…The HUWE1-mediated ubiquitination depends on WIPI2 phosphorylation by MTOR at S395, and this provides another explanation for how MTOR inhibits autophagy [ 167 ]. A more recent study demonstrated that WIPI2 is a substrate of CUL4-RING ubiquitin ligase, which is activated upon mitosis induction and promotes the K48-linked polyubiquitination of WIPI2 and its degradation, again inhibiting autophagy [ 168 ].…”