Protein and gene expression of Ca2+ channel isoforms in murine colon:: effect of inflammation
Protein and gene expression of Ca2+ channel isoforms in murine colon:: effect of inflammation
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DOI：
10.1007/s00424-004-1339-5
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发表时间：
2004-12-01
影响因子：
4.5
通讯作者：
Akbarali, HI
中科院分区：
文献类型：
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作者：
Kang, MH;Morsy, N;Akbarali, HI
L型电压依赖性钙通道（L-VDCC）介导细胞膜去极化引起的钙内流，调节细胞内收缩、分泌、神经传递和基因表达等过程。结肠炎症显著减弱平滑肌中的钙电流;然而，其基础尚不清楚。在这项研究中，我们研究了蛋白质和mRNA表达的两种异构体的Ca（v）1.2，编码的外显子1a或1b。两种异构体在平滑肌细胞中通过Western印迹、免疫组织化学和RT-PCR检测。无论是蛋白质或mRNA的表达，通过实时PCR测量的任一异构体的葡聚糖硫酸钠处理的小鼠结肠肌细胞的影响。在全细胞电压钳实验中，炎症使钙电流的幅度降低了近70%。在对照细胞中，c-src激酶特异性抑制剂PP 2使钙通道电流衰减50 +/- 3%，但在炎症小鼠细胞中仅衰减19 +/- 7%。这些研究表明，结肠炎症后钙通道电流的减少不是由于表达减少，而是由于非受体细胞酪氨酸激酶c-src激酶的调节改变。
L-Type voltage-dependent Ca2+ channels (L-VDCC) mediate calcium influx in response to membrane depolarization and regulate intracellular processes such as contraction, secretion, neurotransmission, and gene expression. Colonic inflammation significantly attenuates calcium currents in smooth muscle; however, the basis for this remains unclear. In this study we examined the protein and mRNA expression of two isoforms of Ca(v)1.2, encoded by either exon 1a or 1b. Both isoforms were detected by Western blots, immunohistochemistry and RT-PCR in smooth muscle cells. Neither the protein nor mRNA expression measured by real-time PCR of either isoforms was affected in colonic myocytes from dextran sulfate sodium-treated mice. In whole-cell voltage-clamp experiments, the amplitude of the calcium currents were decreased by almost 70% by inflammation. The calcium channel currents were attenuated by 50 +/- 3% by the c-src kinase specific inhibitor, PP2, in control cells but only 19 +/- 7% in cells from inflamed mice. These studies suggest that decreased calcium channel currents following colonic inflammation are not due to decreased expression but may result from altered regulation by the non-receptor cellular tyrosine kinase, c-src kinase.