CASP, the alternatively spliced product of the gene encoding the CCAAT-displacement protein transcription factor, is a Golgi membrane protein related to giantin
CASP, the alternatively spliced product of the gene encoding the CCAAT-displacement protein transcription factor, is a Golgi membrane protein related to giantin
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DOI：
10.1091/mbc.e02-06-0349
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发表时间：
2002-11-01
影响因子：
3.3
通讯作者：
Munro, S
中科院分区：
文献类型：
--
作者：
Gillingham, AK;Pfeifer, AC;Munro, S
在高尔基体的膜上发现了越来越多的大卷曲蛋白，并被认为在连接运输小泡和组织高尔基体堆叠中发挥功能。高尔基体卷曲蛋白的一类成员，包括Giantin和Golgin-84，通过单一的C末端跨膜结构域(TMD)锚定在双层上。在这篇文章中，我们报告了另一种哺乳动物螺旋卷曲蛋白CASP的特征，它最初被鉴定为CUTL1的选择性剪接产物。编码CCAAT置换蛋白(CDP)的基因，CDP是果蝇同源域蛋白CUT的人类同源物。我们发现秀丽隐杆线虫的同源物。CDP和CASP也是由单个基因产生的。Casp缺乏CDP的DNA结合基序，先前报道是一种核蛋白。在这里，我们证明了它实际上是一个具有C-末端TMD的高尔基体蛋白，并在其TMD上与Giantin和Golgin-84共享保守的组氨酸。然而，与这些蛋白不同的是，CASP在酿酒酵母中有一个同源物，我们称之为COY1。COY1的缺失不会影响细胞的活力，但显著地恢复了缺乏高尔基可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体Gos1p的细胞的正常生长。在缺乏Gos1p的细胞中，保守的组氨酸是Coy1p活性所必需的，这表明这些跨膜高尔基体卷曲蛋白的TMD直接参与了它们的功能。
Large coiled-coil proteins are being found in increasing numbers on the membranes of the Golgi apparatus and have been proposed to function in tethering of transport vesicles and in the organization of the Golgi stack. Members of one class of Golgi coiled-coil protein, comprising giantin and golgin-84, are anchored to the bilayer by a single C-terminal transmembrane domain (TMD). In this article, we report the characterization of another mammalian coiled-coil protein, CASP, that was originally identified as an alternatively spliced product of the CUTL1. gene that encodes CCAAT-displacement protein (CDP), the human homologue of the Drosophila homeodomain protein Cut. We find that the Caenorhabditis elegans homologues of. CDP and CASP are also generated from a single gene. CASP lacks the DNA binding motifs of CDP and was previously reported to be a nuclear protein. Herein, we show that it is in fact a Golgi protein with a C-terminal TMD and shares with giantin and golgin-84 a conserved histidine in its TMD. However, unlike these proteins, CASP has a homologue in Saccharomyces cerevisiae, which we call COY1. Deletion of COY1 does not affect viability, but strikingly restores normal growth to cells lacking the Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor Gos1p. The conserved histidine is necessary for Coy1p's activity in cells lacking Gos1p, suggesting that the TMD of these transmembrane Golgi coiled-coil proteins is directly involved in their function.