Pragnell M, Sakamoto J, Jay S D, Campbell K P
Howard Hughes Medical Institute, Program in Neuroscience, University of Iowa College of Medicine, Iowa City 52242.
FEBS Lett. 1991 Oct 21;291(2):253-8. doi: 10.1016/0014-5793(91)81296-k.
A cDNA clone encoding a protein with high homology to the beta-subunit of the rabbit skeletal muscle dihydropyridine-sensitive calcium channel was isolated from a rat brain cDNA library. This rat brain beta-subunit cDNA hybridizes to a 3.4 kb message that is expressed in high levels in the cerebral hemispheres and hippocampus but is significantly reduced in cerebellum. The open reading frame encodes 597 amino acids with a predicted mass of 65 679 Da which is 82% homologous with the skeletal muscle beta-subunit. The brain cDNA encodes a unique 153 amino acid C-terminus and predicts the absence of a muscle-specific 50 amino acid internal segment. It also encodes numerous consensus phosphorylation sites suggesting a role in calcium channel regulation. The corresponding human beta-subunit gene was localized to chromosome 17. Hence the encoded brain beta-subunit, which has a primary structure highly similar to its isoform in skeletal muscle, may have a comparable role as an integral regulatory component of a neuronal calcium channel.
从大鼠脑cDNA文库中分离出一个cDNA克隆，其编码的蛋白质与兔骨骼肌二氢吡啶敏感钙通道的β亚基具有高度同源性。该大鼠脑β亚基cDNA与一个3.4 kb的信使RNA杂交，此信使RNA在大脑半球和海马体中高水平表达，但在小脑中显著减少。开放阅读框编码597个氨基酸，预测分子量为65679 Da，与骨骼肌β亚基的同源性为82%。脑cDNA编码一个独特的153个氨基酸的C末端，并预测不存在肌肉特异性的50个氨基酸内部片段。它还编码许多共有磷酸化位点，提示其在钙通道调节中发挥作用。相应的人类β亚基基因定位于17号染色体。因此，编码的脑β亚基，其一级结构与其在骨骼肌中的同种型高度相似，可能作为神经元钙通道的一个完整调节成分发挥类似作用。
