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Proc Natl Acad Sci U S A. 2018 Feb 13;115(7):E1667-E1674. doi: 10.1073/pnas.1718728115. Epub 2018 Jan 30.

Phosphatidylinositol-(4, 5)-bisphosphate regulates calcium gating of small-conductance cation channel TMEM16F.

Author information

1
Department of Physiology, University of California, San Francisco, CA 94158.
2
Howard Hughes Medical Institute, University of California, San Francisco, CA 94158.
3
Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
4
Department of Physiology, University of California, San Francisco, CA 94158; Lily.Jan@ucsf.edu.

Abstract

TMEM16F, which is activated by elevation of intracellular calcium to trigger phospholipid scrambling and the collapse of lipid bilayer asymmetry to mediate important cellular functions such as blood coagulation, also generates a small-conductance calcium-activated cation current. How TMEM16F activation may be regulated is an open question. By recording TMEM16F Ca2+-activated current, we found that the TMEM16F Ca2+-response is desensitized by a brief exposure to high intracellular Ca2+, which is associated with depletion of phosphatidylinositol-(4, 5)-bisphosphate (PIP2) from the inner leaflet of the membrane. Application of artificial or natural PIP2 restores TMEM16F channel activity. PIP2 modulation of TMEM16F requires the presence of several positively charged amino acids in its cytoplasmic N-terminal domain. TMEM16F interaction with PIP2 works synergistically with membrane depolarization to facilitate Ca2+-gating of TMEM16F. Our study reveals the dependence of TMEM16F activity on phosphoinositides and provides one mechanism for TMEM16F activation to be strictly regulated in the cell membrane.

KEYWORDS:

PIP2; TMEM16F; phosphoinositide; scramblase

PMID:
29382763
PMCID:
PMC5816197
DOI:
10.1073/pnas.1718728115
[Indexed for MEDLINE]
Free PMC Article

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