Apical localization of PMCA2w/b is lipid raft-dependent

Biochem Biophys Res Commun. 2009 Jun 19;384(1):32-6. doi: 10.1016/j.bbrc.2009.04.044. Epub 2009 Apr 18.

Abstract

Alternative splicing of the first intracellular loop differentially targets plasma membrane calcium ATPase (PMCA) isoform 2 to the apical or basolateral membrane in MDCK cells. To determine if the targeting is affected by lipid interactions, we stably expressed PMCA2w/b and PMCA2z/b in MDCK cells, and analyzed the PMCA distribution by confocal fluorescence microscopy and membrane fractionation. PMCA2w/b showed clear apical and lateral distribution, whereas PMCA2z/b was mainly localized to the basolateral membrane. A significant fraction of PMCA2w/b partitioned into low-density membranes associated with lipid rafts. Depletion of membrane cholesterol by methyl-beta-cyclodextrin resulted in reduced lipid raft association and a striking loss of PMCA2w/b from the apical membrane, whereas the lateral localization of PMCA2z/b remained unchanged. Our data indicate that alternative splicing differentially affects the lipid interactions of PMCA2w/b and PMCA2z/b and that the apical localization of PMCA2w/b is lipid raft-dependent and sensitive to cholesterol depletion.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing*
  • Animals
  • Cell Line
  • Dogs
  • Humans
  • Membrane Microdomains / enzymology*
  • Plasma Membrane Calcium-Transporting ATPases / genetics
  • Plasma Membrane Calcium-Transporting ATPases / metabolism*

Substances

  • Plasma Membrane Calcium-Transporting ATPases
  • ATP2B2 protein, human