Structural highlights
Function
[SAC1_YEAST] Phosphoinositide phosphatase that hydrolyzes PtdIns(3)P and PtdIns(4)P. Has low activity towards PtdIns(3,5)P2. May be involved in the coordination of the activities of the secretory pathway and the actin cytoskeleton.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Sac family phosphoinositide (PI) phosphatases are an essential family of CX(5)R(T/S)-based enzymes, involved in numerous aspects of cellular function such as PI homeostasis, cellular signalling, and membrane trafficking. Genetic deletions of several Sac family members result in lethality in animal models and mutations of the Sac3 gene have been found in human hereditary diseases. In this study, we report the crystal structure of a founding member of this family, the Sac phosphatase domain of yeast Sac1. The 2.0 A resolution structure shows that the Sac domain comprises of two closely packed sub-domains, a novel N-terminal sub-domain and the PI phosphatase catalytic sub-domain. The structure further shows a striking conformation of the catalytic P-loop and a large positively charged groove at the catalytic site. These findings suggest an unusual mechanism for its dephosphorylation function. Homology structural modeling of human Fig4/Sac3 allows the mapping of several disease-related mutations and provides a framework for the understanding of the molecular mechanisms of human diseases.
Crystal structure of the yeast Sac1: implications for its phosphoinositide phosphatase function.,Manford A, Xia T, Saxena AK, Stefan C, Hu F, Emr SD, Mao Y EMBO J. 2010 May 5;29(9):1489-98. Epub 2010 Apr 13. PMID:20389282[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hughes WE, Woscholski R, Cooke FT, Patrick RS, Dove SK, McDonald NQ, Parker PJ. SAC1 encodes a regulated lipid phosphoinositide phosphatase, defects in which can be suppressed by the homologous Inp52p and Inp53p phosphatases. J Biol Chem. 2000 Jan 14;275(2):801-8. PMID:10625610
- ↑ Foti M, Audhya A, Emr SD. Sac1 lipid phosphatase and Stt4 phosphatidylinositol 4-kinase regulate a pool of phosphatidylinositol 4-phosphate that functions in the control of the actin cytoskeleton and vacuole morphology. Mol Biol Cell. 2001 Aug;12(8):2396-411. PMID:11514624
- ↑ Manford A, Xia T, Saxena AK, Stefan C, Hu F, Emr SD, Mao Y. Crystal structure of the yeast Sac1: implications for its phosphoinositide phosphatase function. EMBO J. 2010 May 5;29(9):1489-98. Epub 2010 Apr 13. PMID:20389282 doi:10.1038/emboj.2010.57
