The complex of TRIP-Br1 and XIAP ubiquitinates and degrades multiple adenylyl cyclase isoforms

• DOI: 10.7554/elife.28021
• Publication Date: 2017-06-28T12:00:10Z
• Authors: Wenbao Hu; Xiaojie Yu; Zhengzhao Liu; Ying Sun; Xibing Chen; Xin Yang; Xiaofen Li; Wai Kwan Lam; Yuanyuan Duan; Xu Cao; Hermann Steller; Kai Liu; Pingbo Huang
• Keywords: 0301 basic medicine; 572; TRIP-Br1; QH301-705.5; Science; X-Linked Inhibitor of Apoptosis Protein; ubiquitination; Cell Line; Mice; 03 medical and health sciences; XIAP; cAMP; Animals; Humans; Protein Isoforms; Biology (General); degradation; 0303 health sciences; Q; R; Ubiquitination; Nuclear Proteins; Cell Biology; 3. Good health; Proteolysis; Trans-Activators; Medicine; adenylyl cyclase; Adenylyl Cyclases; Transcription Factors

Adenylyl cyclases (ACs) generate cAMP, a second messenger of utmost importance that regulates a vast array of biological processes in all kingdoms of life. However, almost nothing is known about how AC activity is regulated through protein degradation mediated by ubiquitination or other mechanisms. Here, we show that transcriptional regulator interacting with the PHD-bromodomain 1 (TRIP-Br1, Sertad1), a newly identified protein with poorly characterized functions, acts as an adaptor that bridges the interaction of multiple AC isoforms with X-linked inhibitor of apoptosis protein (XIAP), a RING-domain E3 ubiquitin ligase. XIAP ubiquitinates a highly conserved Lys residue in AC isoforms and thereby accelerates the endocytosis and degradation of multiple AC isoforms in human cell lines and mice. XIAP/TRIP-Br1-mediated degradation of ACs forms part of a negative-feedback loop that controls the homeostasis of cAMP signaling in mice. Our findings reveal a previously unrecognized mechanism for degrading multiple AC isoforms and modulating the homeostasis of cAMP signaling.