DISTRIBUTION AND ISOLATION OF 4 LAMININ VARIANTS - TISSUE RESTRICTED DISTRIBUTION OF HETEROTRIMERS ASSEMBLED FROM 5 DIFFERENT SUBUNITS
DISTRIBUTION AND ISOLATION OF 4 LAMININ VARIANTS - TISSUE RESTRICTED DISTRIBUTION OF HETEROTRIMERS ASSEMBLED FROM 5 DIFFERENT SUBUNITS
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DOI：
10.1091/mbc.1.10.731
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发表时间：
1990-09-01
期刊：
影响因子：
--
通讯作者：
SANES, JR
中科院分区：
文献类型：
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作者：
ENGVALL, E;EARWICKER, D;SANES, JR
用免疫荧光法研究了基底膜蛋白、层粘连蛋白和硫球蛋白在人和兔组织中的分布。层粘连蛋白A链存在于上皮基底膜、内皮基底膜和平滑肌基底膜。根据重链M的定义，Merosin存在于横纹肌和周围神经中。A亚基与至少两个B亚基共存：B2加上B1或最近发现的B1同源物S。M亚基最常与B1和B2共存。例外包括肌腱连接，其中M与S共存，以及滋养层基底膜，其中M亚单位与S以及B1共存。胎盘中层粘连蛋白家族的所有五个已知亚基的存在，使得利用亲和层析中的单抗以天然形式分离它们的亲本分子。鉴定出4种不同的异三聚体蛋白：含B1链的层粘连蛋白(A-B1-B2)、含S链的层粘连蛋白(A-S-B2)、含B1的硫蛋白(M-B1-B2)和含S的硫蛋白(M-S-B2)。数据表明，层粘连蛋白家族中的蛋白质是由一条重链和两条轻链组成的杂三聚体；大多数基底膜主要含有一种层粘连蛋白家族的蛋白质；由A亚单位定义的层粘连蛋白的分布比以前认为的要有限得多。
The distribution of subunits of the basement membrane proteins laminin and merosin in human and rabbit tissue was studied by immunofluorescence using monoclonal antibodies. The laminin A chain is present in epithelial, endothelial, and smooth muscle basement membranes. Merosin, as defined by its heavy chain M, is present in striated muscle and peripheral nerve. The A subunit colocalizes with at least with two B subunits: B2 plus either B1 or the recently discovered B1 homologue S. The M subunit most often colocalizes with B1 and B2. Exceptions include the myotendinous junction, where M colocalizes with S, and the trophoblast basement membrane, where the M subunit colocalizes with S as well as B1. The presence of all five known subunits of the laminin family in placenta allowed isolation of their parent molecules in native form by the use of monoclonal antibodies in affinity chromatography. Four different heterotrimeric proteins could be identified: B1 chain-containing laminin (A-B1-B2), S chain-containing laminin (A-S-B2), B1-containing merosin (M-B1-B2), and S-containing merosin (M-S-B2). The data show that the proteins in the laminin family are heterotrimers composed of one heavy and two light chains; that most basement membranes contain predominantly one protein of the laminin family; and that laminin, as defined by the A subunit, has a much more restricted distribution than previously thought.