Open Accessβ-Dystroglycan binds caveolin-1 in smooth muscle: a functional role in caveolae distribution and Ca2+ release
Author(s) -
Pawan Sharma,
Saeid Ghavami,
Gerald L. Stelmack,
Karol D. McNeill,
Mark M. Mutawe,
Thomas Klonisch,
Helmut Unruh,
Andrew J. Halayko
Publication year - 2010
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.066712
Subject(s) - caveolae , biology , microbiology and biotechnology , dystroglycan , caveolin , dystrophin , caveolin 3 , lipid raft , actin cytoskeleton , cytoskeleton , signal transduction , laminin , cell , biochemistry , anatomy , skeletal muscle , extracellular matrix
The dystrophin–glycoprotein complex (DGC) links the extracellular matrix and actin cytoskeleton. Caveolae form membrane arrays on smooth muscle cells; we investigated the mechanism for this organization. Caveolin-1 and β-dystroglycan, the core transmembrane DGC subunit, colocalize in airway smooth muscle. Immunoprecipitation revealed the association of caveolin-1 with β-dystroglycan. Disruption of actin filaments disordered caveolae arrays, reduced association of β-dystroglycan and caveolin-1 to lipid rafts, and suppressed the sensitivity and responsiveness of methacholine-induced intracellular Ca2+ release. We generated novel human airway smooth muscle cell lines expressing shRNA to stably silence β-dystroglycan expression. In these myocytes, caveolae arrays were disorganized, caveolae structural proteins caveolin-1 and PTRF/cavin were displaced, the signaling proteins PLCβ1 and Gαq, which are required for receptor-mediated Ca2+ release, were absent from caveolae, and the sensitivity and responsiveness of methacholine-induced intracellular Ca2+ release, was diminished. These data reveal an interaction between caveolin-1 and β-dystroglycan and demonstrate that this association, in concert with anchorage to the actin cytoskeleton, underpins the spatial organization and functional role of caveolae in receptor-mediated Ca2+ release, which is an essential initiator step in smooth muscle contraction.