The CTLH ubiquitin ligase substrates ZMYND19 and MKLN1 negatively regulate mTORC1 at the lysosomal membrane.

ABSTRACT: Most Epstein-Barr virus-associated gastric carcinoma (EBVaGC) harbor non-silent mutations that activate phosphoinositide 3 kinase (PI3K) to drive downstream metabolic signaling. To gain insights into PI3K/mTOR pathway dysregulation in this context, we perform a human genome-wide CRISPR/Cas9 screen for hits that synergistically blocked EBVaGC proliferation together with the PI3K antagonist alpelisib. Multiple subunits of carboxy terminal to LisH (CTLH) E3 ligase, including the catalytic MAEA subunit, are among top screen hits. CTLH negatively regulates gluconeogenesis in yeast, but not in higher organisms. The CTLH substrates MKLN1 and ZMYND19, which highly accumulated upon MAEA knockout, associate with one another and with lysosome outer membranes to inhibit mTORC1. Rather than perturbing

SUBMITTER: Wang Y 

PROVIDER: S-EPMC12663577 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature