title: Apical localization of PMCA2w/b is lipid raft-dependent.
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.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Yuning
authors.initials: Y
authors.lastname: Xiong
authors.forename: Géza
authors.initials: G
authors.lastname: Antalffy
authors.forename: Agnes
authors.initials: A
authors.lastname: Enyedi
authors.forename: Emanuel E
authors.initials: EE
authors.lastname: Strehler
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002460:Cell Line; D004285:Dogs; D006801:Humans; D021962:Membrane Microdomains / Q000201:enzymology*; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*
chemical_list: D053499:Plasma Membrane Calcium-Transporting ATPases; C506958:ATP2B2 protein, human