Burette Alain, Rockwood Julia M, Strehler Emanuel E, Weinberg Richard J
Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
J Comp Neurol. 2003 Dec 22;467(4):464-76. doi: 10.1002/cne.10933.
Regulation of cytoplasmic calcium is crucial both for proper neuronal function and cell survival. The concentration of Ca2+ in cytoplasm of a neuron at rest is 10,000 times lower than in the extracellular space, pointing to the importance of the transporters that extrude intracellular Ca2+. The family of plasma membrane calcium-dependent ATPases (PMCAs) represent a major component of the Ca2+ regulatory system. However, little information is available on the regional and cellular distribution of these calcium pumps. We used immunohistochemistry to investigate the distribution of each of the four PMCA isoforms (PMCA1-4) in the rat brain. Each isoform exhibited a remarkably precise and distinct pattern of distribution. In many cases, PMCA isoforms in a single brain structure were differentially expressed within different classes of neurons, and within different subcellular compartments. These data show that each isoform is independently organized and suggest that PMCAs may play a more complex role in calcium homeostasis than generally recognized.
细胞质钙的调节对于神经元的正常功能和细胞存活都至关重要。静息状态下神经元细胞质中Ca2+的浓度比细胞外空间低10000倍，这表明将细胞内Ca2+排出的转运蛋白的重要性。质膜钙依赖性ATP酶（PMCA）家族是Ca2+调节系统的主要组成部分。然而，关于这些钙泵的区域和细胞分布的信息很少。我们使用免疫组织化学方法研究了大鼠脑中四种PMCA亚型（PMCA1 - 4）各自的分布情况。每种亚型都呈现出非常精确且独特的分布模式。在许多情况下，单一脑结构中的PMCA亚型在不同类型的神经元以及不同的亚细胞区室中差异表达。这些数据表明每种亚型都是独立组织的，并且提示PMCA在钙稳态中可能发挥比普遍认为的更为复杂的作用。
