The rapid proximity labeling system PhastID identifies ATP6AP1 as an unconventional GEF for Rheb

• DOI: 10.1038/s41422-024-00938-z
• Publication Date: 2024-03-06T11:03:07Z
• Authors: Ran Feng; Feng Liu; Ruofei Li; Zhifen Zhou; Zhuoheng Lin; Song Lin; Shengcheng Deng; Yingying Li; Baoting Nong; Ying Xia; Zhiyi Li; Xiaoqin Zhong; Shuhan Yang; Gang Wan; Wenbin Ma; Su Wu; Zhou Songyang
• Keywords: RHEB; Small GTPase

Abstract Rheb is a small G protein that functions as the direct activator of mechanistic target rapamycin complex 1 (mTORC1) to coordinate signaling cascades in response nutrients and growth factors. Despite extensive studies, guanine nucleotide exchange factor (GEF) directly activates remains unclear, at least part due dynamic transient nature protein–protein interactions (PPIs) are hallmarks signal transduction. Here, we report development rapid robust proximity labeling system named Pyrococcus horikoshii biotin ligase ( Ph BPL)-assisted identification (PhastID) detail insulin-stimulated changes Rheb-proximity networks were identified using PhastID. In particular, found lysosomal V-ATPase subunit ATP6AP1 could dynamically interact with Rheb. bind through its last 12 amino acids utilizes tri-aspartate motif highly conserved C-tail enhance GTP loading. fact, targeting block activation inhibit cancer cell proliferation migration. Our findings highlight versatility PhastID mapping PPIs live cells, reveal ATP6AP1’s role an unconventional GEF for Rheb, underscore importance integrating mTORC1 signals filling missing link Rheb/mTORC1 activation.