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

Journal Article · Mon Aug 25 04:00:00 EDT 2014 · J. Cell Biol.

DOI:https://doi.org/10.1083/jcb.201404041· OSTI ID:1150770

Cai, Yiying; Deng, Yongqiang; Horenkamp, Florian; Reinisch, Karin M.; Burd, Christopher G. ^[1]

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1. Yale-MED

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.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: NIH
• OSTI ID: 1150770
• Journal Information: J. Cell Biol., Journal Name: J. Cell Biol. Journal Issue: (4) ; 08, 2014 Vol. 206
• Country of Publication: United States
• Language: ENGLISH