A 240 KDA PROTEIN REPRESENTS THE COMPLETE BETA-SUBUNIT OF THE CYCLIC NUCLEOTIDE-GATED CHANNEL FROM ROD PHOTORECEPTOR
A 240 KDA PROTEIN REPRESENTS THE COMPLETE BETA-SUBUNIT OF THE CYCLIC NUCLEOTIDE-GATED CHANNEL FROM ROD PHOTORECEPTOR
复制标题
DOI：
10.1016/0896-6273(95)90151-5
复制
发表时间：
1995-09-01
期刊：
影响因子：
16.2
通讯作者：
MOLDAY, RS
中科院分区：
文献类型：
--
作者：
KORSCHEN, HG;ILLING, M;MOLDAY, RS
杆状感受器的环核苷酸门控通道由两个不同的亚基(α和β)组成，α亚基的性质可以通过与同源多肽(称为β亚基)的共表达来改变，α亚基本身可以形成功能通道。然而，杆状感光细胞膜的α亚基与240 kDa的蛋白交配，明显大于这个假定的β亚基。我们现在通过肽序列测定和cDNA的克隆和功能表达证明，240 kDa的蛋白代表了具有不寻常的两部分结构的完整的β亚基。N-末端部分基本上与富含谷氨酸的蛋白(GARP)相同，而C-末端部分与先前克隆的人类“β亚基”高度同源，在HEK 293细胞中表达完整的β亚基导致了一种多肽，其表观分子量与天然杆状通道的240 kDa蛋白质相同。α亚基和全长β亚基的共表达产生具有天然通道特性的杂寡体通道。
The cyclic nucleotide-gated channel from rod photoreceptors is composed of two distinct subunits (alpha and beta), The properties of the alpha subunit, which can form functional channels by itself, are modified by coexpression with a homologous polypeptide, designated the beta subunit. However, the alpha subunit from rod photoreceptor membranes copurifies with a 240 kDa protein that is significantly larger than this putative beta subunit, We now demonstrate by peptide sequencing and by cloning and functional expression of cDNA that the 240 kDa protein represents the complete beta subunit with an unusual bipartite structure. The N-terminal part is essentially identical to a glutamic acid-rich protein (GARP), whereas the C-terminal part is highly homologous to the previously cloned human ''beta subunit,'' Expression of the complete beta subunit in HEK 293 cells results in a polypeptide with the same apparent molecular weight as the 240 kDa protein of the native rod channel. Coexpression of the alpha subunit with the full-length beta subunit yields hetero-oligomeric channels with properties characteristic of the native channel.