TY - JOUR
T1 - Molecular cloning of calcium channel α2δ-subunits from rat atria and the differential regulation of their expression by IGF-1
AU - Chu, Po Ju
AU - Best, Philip M.
PY - 2003/2/1
Y1 - 2003/2/1
N2 - Calcium channels are multimeric proteins consisting of pore-forming (α1) and auxiliary (α2δ, β, γ) subunits. The auxiliary α2δ-subunit regulates calcium current density and activation/inactivation kinetics when co-expressed with some, but not all, α1-subunits. Here we report the differential expression of three α2δ-subunit cDNAs in rat atria, atrial myocytes and ventricle, and demonstrate that IGF-1 selectively increases the expression of the α2δ-3 mRNA in the atria. mRNA encoding the α2δ-1- and α2δ-2-subunits, but not the α2δ-3-subunit, is detected in the rat ventricle whereas all three transcripts are found in atrial tissue. Analysis of the rat α2δ-1 cDNA sequence indicates that the atria express the α2δ-1e alternatively spliced isoform of this gene. The complete cDNA sequences of the α2δ-2- and α2δ-3-subunits from rat atria were determined and found to share 96% and 95% identity, respectively, with their counterparts in mouse. Treatment of acutely cultured atrial myocytes with IGF-1 caused a significant increase of the amount of α2δ-3, but not α2δ-1 or α2δ-2, mRNA. Both L-type and T-type calcium currents are recorded from cardiac tissue although their expression is regionally specific and changes with age and physiological state. Differential regulation of the expression of α2δ-subunit genes is likely to contribute to alterations in the expression of calcium current in the mammalian heart.
AB - Calcium channels are multimeric proteins consisting of pore-forming (α1) and auxiliary (α2δ, β, γ) subunits. The auxiliary α2δ-subunit regulates calcium current density and activation/inactivation kinetics when co-expressed with some, but not all, α1-subunits. Here we report the differential expression of three α2δ-subunit cDNAs in rat atria, atrial myocytes and ventricle, and demonstrate that IGF-1 selectively increases the expression of the α2δ-3 mRNA in the atria. mRNA encoding the α2δ-1- and α2δ-2-subunits, but not the α2δ-3-subunit, is detected in the rat ventricle whereas all three transcripts are found in atrial tissue. Analysis of the rat α2δ-1 cDNA sequence indicates that the atria express the α2δ-1e alternatively spliced isoform of this gene. The complete cDNA sequences of the α2δ-2- and α2δ-3-subunits from rat atria were determined and found to share 96% and 95% identity, respectively, with their counterparts in mouse. Treatment of acutely cultured atrial myocytes with IGF-1 caused a significant increase of the amount of α2δ-3, but not α2δ-1 or α2δ-2, mRNA. Both L-type and T-type calcium currents are recorded from cardiac tissue although their expression is regionally specific and changes with age and physiological state. Differential regulation of the expression of α2δ-subunit genes is likely to contribute to alterations in the expression of calcium current in the mammalian heart.
KW - Calcium channels
KW - IGF-1
KW - αδ-subunits
UR - http://www.scopus.com/inward/record.url?scp=0037330689&partnerID=8YFLogxK
U2 - 10.1016/S0022-2828(02)00313-9
DO - 10.1016/S0022-2828(02)00313-9
M3 - 文章
C2 - 12606261
AN - SCOPUS:0037330689
SN - 0022-2828
VL - 35
SP - 207
EP - 215
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
IS - 2
ER -