Novel hexad repeats conserved in a putative transporter with restricted expression in cell types associated with growth, calcium exchange and homeostasis
Novel hexad repeats conserved in a putative transporter with restricted expression in cell types associated with growth, calcium exchange and homeostasis
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DOI：
10.1016/j.yexcr.2003.10.002
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发表时间：
2004-02-01
影响因子：
3.7
通讯作者：
Wookey, PJ
中科院分区：
文献类型：
--
作者：
Brasier, G;Tikellis, C;Wookey, PJ
描述了一种具有12个跨膜区段的转运蛋白。在细胞质氨基末端结构域内，在人、小鼠、大鼠和猪中几个新的六联体重复序列是保守的，其中4到6个具有标准形式PS_S_H⁺。在羧基末端结构域，一个多聚谷氨酸序列（5 - 8个）是保守的。在分泌生长激素和催乳素的成年垂体的嗜酸细胞中鉴定出该转运蛋白的局限性表达。在胎儿中，表达局限于破骨细胞、软骨细胞、甲状腺、垂体、中枢神经系统、眼睛、肝脏和心脏。特别是，在与快速钙交换相关的结构中发现有表达，包括视网膜、心肌细胞以及表达钙调节分子的胎盘内卵黄囊。此外，在破骨细胞和肾脏中，在肾单位远端部分和集合管内发现的表达与在钙稳态中的作用是一致的。在人垂体中表达四种mRNA转录本，在小鼠肾脏中表达三种mRNA转录本。在发育中的小鼠肾脏中，每种转录本的量是不同的，这表明多种转录本可能在不同的生理状态下差异表达。我们提出该转运蛋白对一种钙 - 螯合剂复合物具有特异性，并且对生长和钙代谢是重要的。（C）2003爱思唯尔公司。保留所有权利。
A transport protein is described with 12 transmembrane spans. Within the cytoplasmic amino-terminal domain, several novel hexad repeats are conserved in human, mouse, rat and pig, four to six of which had the canonical form PS_S_H+. In the carboxyl-terminal domain, a polyglutamate sequence (5-8) is conserved. Restricted expression of the transporter was identified in acidophil cells of the adult pituitary that secrete growth hormone and prolactin. In the fetus, expression was restricted to osteoclasts, chondrocytes, thyroid, pituitary, central nervous system, eye, liver and heart. In particular, expression was found in structures associated with rapid calcium exchange including the retina, cardiomyocytes and in the intraplacental yolk sac that expresses calcitropic molecules. Furthermore, expression found in osteoclasts and kidney, within the distal portions of nephrons and collecting ducts, was consistent with a role in calcium homeostasis. In human pituitary, four mRNA transcripts, and in mouse kidney, three mRNA transcripts were expressed. In developing mouse kidney, the amount of each transcript varied that suggested the multiple transcripts might be differentially expressed in different physiological states. We propose that the transporter is specific for a calcium-chelator complex and is important for growth and calcium metabolism. (C) 2003 Elsevier Inc. All rights reserved.