Amino acid sequence of a novel integrin beta 4 subunit and primary expression of the mRNA in epithelial cells.
Amino acid sequence of a novel integrin beta 4 subunit and primary expression of the mRNA in epithelial cells.
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DOI：
10.1002/j.1460-2075.1990.tb08170.x
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发表时间：
1990-03
期刊：
影响因子：
--
通讯作者：
'. ShintaroSuzuki;Y. Naitoh
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文献类型：
--
作者：
'. ShintaroSuzuki;Y. Naitoh
使用聚合酶链反应，我们已经分离出编码新的整合素β亚基-β 4的cDNA克隆。其cDNA全长为5676 bp，含有一个长的编码序列（5256 bp）、一个多聚腺苷酸化信号和一个poly（A）尾。推导的1752个氨基酸的序列在整联蛋白β亚基中是独特的。它含有一个推定的信号序列以及一个跨膜结构域，该结构域将分子分为N端侧的细胞外结构域和C端侧的细胞质结构域。细胞外结构域表现出与其他整联蛋白β亚基相似的富含半胱氨酸的基序的4倍重复。然而，胞外结构域的某些特征对于β 4亚基序列是独特的。在其他成熟β亚基的细胞外结构域内发现的56个保守半胱氨酸残基中，8个这样的残基从β 4亚基序列中缺失。胞质结构域比其他β亚基（约50个氨基酸）大得多（约1000个氨基酸），并且与它们没有显著的同源性。蛋白质同源性搜索显示，β 4亚基胞质结构域有四个重复单元，与纤连蛋白所表现出的III型重复同源。β 4亚基mRNA主要在上皮细胞中表达。限制性表达和新的结构特征将整合素β 4亚基与其他整合素β亚基区分开来。
Using the polymerase chain reaction, we have isolated cDNA clones that encode a new integrin beta subunit‐‐beta 4. Its cDNA, which is 5676 bp in length, has one long coding sequence (5256 bp), a polyadenylation signal and a poly(A) tail. The deduced sequence of 1752 amino acids is unique among the integrin beta subunits. It contains a putative signal sequence as well as a transmembrane domain that divides the molecule into an extracellular domain at the N‐terminal side and a cytoplasmic domain at the C‐terminal side. The extracellular domain exhibits a 4‐fold repeat of cysteine‐rich motif similar to those of other integrin beta subunits. Certain features of the extracellular domain, however, are unique to the beta 4 subunit sequence. Of the 56 conserved cysteine residues found within the extracellular domain of other mature beta subunits, eight such residues are deleted from the beta 4 subunit sequence. The cytoplasmic domain is much larger (approximately 1000 amino acids) than those of other beta subunits (approximately 50 amino acids) and has no significant homology with them. A protein homology search revealed that the beta 4 subunit cytoplasmic domain has four repeating units that are homologous to the type III repetition exhibited by fibronectin. The beta 4 subunit mRNA was expressed primarily in epithelial cells. The restricted expression and the new structural features distinguish the integrin beta 4 subunit from other integrin beta subunits.