Ca2+-ATPase protein expression in mammary tissue
Ca2+-ATPase protein expression in mammary tissue
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DOI：
10.1152/ajpcell.2000.279.5.c1595
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发表时间：
2000-11-01
影响因子：
5.5
通讯作者：
Horst, RL
中科院分区：
文献类型：
--
作者：
Reinhardt, TA;Filoteo, AG;Horst, RL
本研究检测了大鼠乳腺组织质膜Ca ~（2+）-ATP酶（PMCAs）和高尔基体分泌途径Ca ~（2+）-ATP酶（SPCA）的蛋白表达。随着泌乳的开始，PMCA蛋白的表达急剧增加，这增加了牛奶产量。乳腺PMCA主要为PMCA 2b，但类似于比预期大4，000道尔顿。RT-PCR显示，初级乳腺PMCA 2b转录物在剪接位点A处被选择性剪接，以包括额外的135 bp，导致45个氨基酸的插入。这种拼接形式被指定为2bw。PMCA 2bw分泌到乳汁中，与乳脂球膜相关。因此，PMCA 2bw位于分泌细胞的顶膜上。在乳腺组织中发现少量的PMCA 1b和4 b蛋白。PMCA 4 b是发育组织中表达的主要PMCA，其水平随着泌乳开始而下降。PMCA 1b表达在哺乳期适度增加。SPCA蛋白表达增加1周前分娩，并增加进一步哺乳进行。PMCA 2b的丰度和细胞定位表明，它是重要的宏观钙稳态在泌乳组织。SPCA的表达模式和丰度表明它是高尔基体Ca ~（2+）-ATP酶的候选者。
Protein expression of plasma membrane Ca2+-ATPases (PMCAs) and the putative Golgi secretory pathway Ca2+-ATPase (SPCA) was examined in rat mammary tissue. As lactation started, PMCA protein expression increased dramatically, and this increased expression paralleled milk production. Mammary PMCA was primarily PMCA2b but was similar to 4,000 daltons larger than expected. RT-PCR showed that the primary mammary PMCA2b transcript was alternatively spliced, at splice site A, to include an additional 135 bp, resulting in the insertion of 45 amino acids. This splice form is designated 2bw. PMCA2bw is secreted into milk, associated with the milk fat globule membrane. Therefore, PMCA2bw is located on the apical membrane of the secretory cell. Smaller amounts of PMCA1b and 4b protein were found in mammary tissue. PMCA4b was the major PMCA expressed in developing tissue, and its level declined as lactation started. PMCA1b expression increased moderately during lactation. SPCA protein expression increased 1 wk before parturition and increased further as lactation proceeded. The abundance and cell location of PMCA2b suggest that it is important for macro-Ca2+ homeostasis in lactating tissue. The pattern of expression and abundance of SPCA suggest that it is a candidate for the Golgi Ca2+-ATPase.