Expression and Functional Analysis of a Novel Isoform of Gicerin, an Immunoglobulin Superfamily Cell Adhesion Molecule (*)
Expression and Functional Analysis of a Novel Isoform of Gicerin, an Immunoglobulin Superfamily Cell Adhesion Molecule (*)
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免疫球蛋白超家族细胞粘附分子 Gicerin 的新型异构体的表达和功能分析 (*)
DOI：
10.1074/jbc.270.48.28681
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
N. Miki
中科院分区：
文献类型：
--
作者：
E. Taira;T. Nagino;H. Taniura;N. Takaha;Cheol‐Hee Kim;C. Kuo;Bing;Hiroshi Higuchi;N. Miki
我们克隆了甘油的新 cDNA，甘油是一种属于免疫球蛋白超家族的细胞粘附分子。两种 gicerin 亚型具有相同的胞外结构域，具有 5 个免疫球蛋白样环结构和一个与 s-gicerin 一样的跨膜结构域，但在细胞质尾部结构域上有所不同。由于新鉴定的形式比之前报道的形式具有更大的细胞质结构域，因此我们分别将它们称为 l-gicerin 和 s-gicerin。 L-甘油是从含有 s-甘油 mRNA 中未发现的插入序列的不同 mRNA 转录而来，该插入序列导致胞质结构域的编码区发生移码。先前的研究表明，甘油在鸡砂囊平滑肌中显示出 82 和 90 kDa 的双峰带。我们报告 82-kDa 蛋白对应于 s-gicerin，90-kDa 蛋白对应于 l-gicerin。我们还发现两种甘油异构体在发育中的神经系统中表达存在差异。对稳定转染子中这些甘油同工型的功能分析表明，它们在同种粘附特性以及用神经突生长因子测定的异种细胞粘附方面具有不同。此外，这些亚型通过其同质粘附而具有促进神经突的活性，但其促进神经突生长的能力不同。
We have cloned a novel cDNA of gicerin, a cell adhesion molecule belonging to the immunoglobulin superfamily. Both gicerin isoforms share the same extracellular domain, which has five immunoglobulin-like loop structures and a transmembrane domain as s-gicerin, but differ in the cytoplasmic tail domain. As the newly identified form has a larger cytoplasmic domain than the previously reported form, we refer to them as l-gicerin and s-gicerin, respectively. l-gicerin is transcribed from a distinct mRNA containing an inserted sequence not found in s-gicerin mRNA which caused a frameshift for the coding region for a cytoplasmic domain. Previous studies demonstrated that gicerin showed a doublet band of 82 and 90 kDa in chicken gizzard smooth muscle. We report that the 82-kDa protein corresponds to s-gicerin and the 90-kDa protein to l-gicerin. We also found that the two gicerin isoforms are expressed differentially in the developing nervous system. Functional analysis of these gicerin isoforms in stable transfectants revealed that they had differ in their homophilic adhesion properties, as well as in heterophilic cell adhesion assayed with neurite outgrowth factor. In addition, these isoforms have neurite-promoting activity by their homophilic adhesion, but differ in their ability to promote neurite outgrowth.