Sac1–Vps74 structure reveals a mechanism to terminate phosphoinositide signaling in the Golgi apparatus

Autor: Christopher G. Burd, Yiying Cai, Yongqiang Deng, Florian A. Horenkamp, Karin M. Reinisch
Rok vydání: 2014
Předmět:
Zdroj: The Journal of Cell Biology
ISSN: 1540-8140
0021-9525
DOI: 10.1083/jcb.201404041
Popis: Characterization of the structure of the N-terminal portion of yeast Sac1 in complex with the phosphatidylinositol 4-kinase effector Vps74 identifies how Sac1 is directed to dephosphorylate PtdIns4P in the Golgi.
Sac1 is a phosphoinositide phosphatase of the endoplasmic reticulum and Golgi apparatus that controls organelle membrane composition principally via regulation of phosphatidylinositol 4-phosphate signaling. We present a characterization of the structure of the N-terminal portion of yeast Sac1, containing the conserved Sac1 homology domain, in complex with Vps74, a phosphatidylinositol 4-kinase effector and the orthologue of human GOLPH3. The interface involves the N-terminal subdomain of the Sac1 homology domain, within which mutations in the related Sac3/Fig4 phosphatase have been linked to Charcot–Marie–Tooth disorder CMT4J and amyotrophic lateral sclerosis. Disruption of the Sac1–Vps74 interface results in a broader distribution of phosphatidylinositol 4-phosphate within the Golgi apparatus and failure to maintain residence of a medial Golgi mannosyltransferase. The analysis prompts a revision of the membrane-docking mechanism for GOLPH3 family proteins and reveals how an effector of phosphoinositide signaling serves a dual function in signal termination.
Databáze: OpenAIRE