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Differential translation of the α‐1 isoforms of L‐type calcium channel in rat brain and other tissues
Author(s) -
Khan Islam,
Ahmad Suhail,
Thomas Nancy
Publication year - 1998
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1002/iub.7510450507
Subject(s) - gene isoform , isozyme , exon , alternative splicing , biology , microbiology and biotechnology , amino acid , polyclonal antibodies , messenger rna , protein subunit , rna splicing , transmembrane protein , biochemistry , gene , enzyme , antibody , rna , genetics , receptor
L‐Type voltage operated calcium channel plays an important role in the contraction‐relaxation of muscle cells. The α‐1 subunit of this pentameric protein performs catalytic functions. Multiple mRNA isoforms of this subunit are generated by alternative splicing. For example, an exon encoding 11 amino acids (aa) between the third and fourth transmembrane domains produces two mRNA isoforms in gastrointestinal (GI) tract. The corresponding exon in brain encodes 15 aa. Whether the α‐1 mRNA isoforms are translated into the corresponding isozymes remain unknown. To address this issue and to characterize the exon in brain, isozymes specific anti‐peptide polyclonal antibodies were raised. Both the antibodies reacted with a protein of Mr 180 kDa in the heart and GI‐tract, while no reaction was obtained in the kidney or liver. Brain expressed the isoform containing the same exon encoding 11 amino acids present in GI‐tract, but the corresponding isozymes were of Mr 145–150 kDa. These findings suggest a tissue‐specific translation of the α‐1 isozymes.