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J Lipid Res. 2016 Apr;57(4):650-62. doi: 10.1194/jlr.M066381. Epub 2016 Feb 26.

Structural elements that govern Sec14-like PITP sensitivities to potent small molecule inhibitors.

Author information

1
Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128.
2
Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 Chemistry, Texas A&M University, College Station, TX 77843-2128 tripathi@tamhsc.edu vytas@tamhsc.edu.
3
Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 tripathi@tamhsc.edu vytas@tamhsc.edu.

Abstract

Sec14-like phosphatidylinositol transfer proteins (PITPs) play important biological functions in integrating multiple aspects of intracellular lipid metabolism with phosphatidylinositol-4-phosphate signaling. As such, these proteins offer new opportunities for highly selective chemical interference with specific phosphoinositide pathways in cells. The first and best characterized small molecule inhibitors of the yeast PITP, Sec14, are nitrophenyl(4-(2-methoxyphenyl)piperazin-1-yl)methanones (NPPMs), and a hallmark feature of NPPMs is their exquisite targeting specificities for Sec14 relative to other closely related Sec14-like PITPs. Our present understanding of Sec14::NPPM binding interactions is based on computational docking and rational loss-of-function approaches. While those approaches have been informative, we still lack an adequate understanding of the basis for the high selectivity of NPPMs among closely related Sec14-like PITPs. Herein, we describe a Sec14 motif, which we term the VV signature, that contributes significantly to the NPPM sensitivity/resistance of Sec14-like phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer proteins. The data not only reveal previously unappreciated determinants that govern Sec14-like PITP sensitivities to NPPMs, but enable predictions of which Sec14-like PtdIns/PtdCho transfer proteins are likely to be NPPM resistant or sensitive based on primary sequence considerations. Finally, the data provide independent evidence in support of previous studies highlighting the importance of Sec14 residue Ser173 in the mechanism by which NPPMs engage and inhibit Sec14-like PITPs.

KEYWORDS:

lipid signaling; lipid transfer proteins; phosphatidylcholine; phosphatidylinositol transfer protein; phosphoinositides; phospholipids

PMID:
26921357
PMCID:
PMC4808773
DOI:
10.1194/jlr.M066381
[Indexed for MEDLINE]
Free PMC Article

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