Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
J Struct Biol. 2010 May;170(2):398-405. doi: 10.1016/j.jsb.2010.02.004. Epub 2010 Feb 13.
Laminins are large heterotrimeric, multidomain proteins that play a central role in organising and establishing all basement membranes. Despite a total of 45 potential heterotrimeric chain combinations formed through the coiled-coil domain of the 11 identified laminin chains (alpha1-5, beta1-3, gamma1-3), to date only 15 different laminin isoforms have been reported. This observation raises the question whether laminin assembly is regulated by differential gene expression or specific chain recognition. To address this issue, we here perform a complete analysis of laminin chain assembly and specificity. Using biochemical and biophysical techniques, all possible heterotrimeric combinations from recombinant C-terminal coiled-coil fragments of all chains were analysed. Apart from laminin 323 (alpha3, beta2, gamma3), for which no biochemical evidence of its existence in vivo is available, these experiments confirmed all other known laminin isoforms and identified two novel potential chain combinations, laminins 312 (alpha3, beta1, gamma2) and 422 (alpha4, beta2, gamma4). Our findings contribute to the understanding of basement membrane structure, function and diversity.
层粘连蛋白是一种大型的异三聚体、多结构域蛋白，在组织和建立所有基底膜方面起着核心作用。尽管通过 11 种已鉴定的层粘连蛋白链（alpha1-5、beta1-3、gamma1-3）的卷曲螺旋域可以形成总共 45 种潜在的异三聚体链组合，但迄今为止仅报道了 15 种不同的层粘连蛋白同工型。这一观察结果提出了一个问题，即层粘连蛋白组装是否受到差异基因表达或特定链识别的调节。为了解决这个问题，我们在这里对层粘连蛋白链组装和特异性进行了全面分析。使用生化和生物物理技术，分析了所有链的重组 C 端卷曲螺旋片段的所有可能异三聚体组合。除了层粘连蛋白 323（alpha3、beta2、gamma3），因为没有其在体内存在的生化证据，这些实验证实了所有其他已知的层粘连蛋白同工型，并鉴定了两种新的潜在链组合，层粘连蛋白 312（alpha3、beta1、gamma2）和 422（alpha4、beta2、gamma4）。我们的研究结果有助于理解基底膜的结构、功能和多样性。
