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β Subunit heterogeneity of L‐type Ca 2+ channels in smooth muscle tissues
Author(s) -
Reimer Daniel,
Huber Irene G.,
Garcia Maria L.,
Haase Hannelore,
Striessnig Jörg
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01124-8
Subject(s) - protein subunit , gene isoform , immunoprecipitation , gating , chemistry , microbiology and biotechnology , biology , biophysics , biochemistry , gene
Various β subunit isoforms stabilize different gating properties of voltage‐gated L‐type Ca 2+ channels. We therefore investigated the expression of Ca 2+ channel β subunit isoforms in different smooth muscle types on the protein level by immunoblotting and immunoprecipitation employing β subunit‐selective sequence‐directed antibodies. From the four known β subunit isoforms only β2 and β3 were detected in porcine uterus, bovine trachea and bovine aorta membranes. Multiple immunoreactive β2 bands were detected in a tissue‐selective manner indicating structural heterogeneity of β2. Immunoprecipitation of (+)‐[ 3 H]isradipine‐prelabeled channels revealed that β2 and β3 participate in Ca 2+ channel formation in uterus and trachea, and β3 in aortic smooth muscle. We conclude that β2 and β3 subunits form L‐type Ca 2+ channels in smooth muscle tissues. This subunit heterogeneity may be important to fine‐tune channel function.