MEROSIN, A TISSUE-SPECIFIC BASEMENT-MEMBRANE PROTEIN, IS A LAMININ-LIKE PROTEIN
MEROSIN, A TISSUE-SPECIFIC BASEMENT-MEMBRANE PROTEIN, IS A LAMININ-LIKE PROTEIN
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DOI：
10.1073/pnas.87.9.3264
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发表时间：
1990-05-01
影响因子：
11.1
通讯作者：
ENGVALL, E
中科院分区：
文献类型：
--
作者：
EHRIG, K;LEIVO, I;ENGVALL, E
Merosin是一种基底膜相关蛋白，存在于胎盘、横纹肌和周围神经中。从胎盘cDNA表达文库中分离到一个3.6千碱基的merosin cDNA克隆。该克隆包含一个3.4千碱基的开放阅读框，其中3”部分包含merosin蛋白水解片段的蛋白质序列。推导出的merosin多肽的氨基酸序列与层粘连蛋白400 kda A链cooh末端的氨基酸序列相似。这部分层粘连蛋白在层粘连蛋白交叉的长臂末端形成大的球体，被认为包含神经突促进位点和主要的细胞结合位点是层粘连蛋白。merosin与层粘连蛋白A链在该区域的序列一致性接近40%。一种针对merosin cDNA序列中间合成肽的抗血清在胎盘提取物中鉴定出一个300 kda的多肽，表明该merosin多肽的大小与层粘连蛋白a链相似。完整的merosin从胎盘提取物中分离出来，并与层粘连蛋白B链共价结合，具有与层粘连蛋白相似的交叉结构。merosin和层粘连蛋白之间的相似性表明这两种蛋白都是基底膜蛋白家族的成员。
Merosin is a basement membrane-associated protein found in placenta, striated muscle, and peripheral nerve. A 3.6-kilobase merosin cDNA clone was isolated from a placental cDNA expression library. The clone contained a 3.4-kilobase open reading frame, the 3'' portion of which includes protein sequences of proteolytic fragments of merosin. The deduced amino acid sequence of the merosin polypeptide was similar to that of the COOH-terminal region of the 400-kDa A chain of laminin. This part of laminin forms the large globule at the end of the long arm of the laminin cross and is thought to contain the neurite-promoting site and the major cell binding site(s) is laminin. The sequence identity between merosin and the laminin A chain is this region is nearly 40%. An antiserum against a synthetic peptide from the middle of the merosin cDNA sequence identified a 300-kDa polypeptide in placental extracts, indicating that the merosin polypeptide is similar in size to the laminin A chain. Intact merosin was isolated from placental extracts and shown to be covalently associated with the laminin B chains and to have a cross-like structure similar to that of laminin. The similarities between merosin and laminin show that both proteins are members of the same family of basement membrane proteins.