Ardini E, Pesole G, Tagliabue E, Magnifico A, Castronovo V, Sobel M E, Colnaghi M I, Ménard S
Division of Experimental Oncology E, Istituto Nazionale Tumori, Milan, Italy.
Mol Biol Evol. 1998 Aug;15(8):1017-25. doi: 10.1093/oxfordjournals.molbev.a026000.
The 67-kDa laminin receptor (67LR) is a nonintegrin cell surface receptor that mediates high-affinity interactions between cells and laminin. Overexpression of this protein in tumor cells has been related to tumor invasion and metastasis. Thus far, only a full-length gene encoding a 37-kDa precursor protein (37LRP) has been isolated. The finding that the cDNA for the 37LRP is virtually identical to a cDNA encoding the ribosomal protein p40 has suggested that 37LRP is actually a component of the translational machinery, with no laminin-binding activity. On the other hand, a peptide of 20 amino acids deduced from the sequence of 37LR/p40 was shown to exhibit high laminin-binding activity. The evolutionary relationship between 23 sequences of 37LRP/p40 proteins was analyzed. This phylogenetic analysis indicated that all of the protein sequences derive from orthologous genes and that the 37LRP is indeed a ribosomal protein that acquired the novel function of laminin receptor during evolution. The evolutionary analysis of the sequence identified as the laminin-binding site in the human protein suggested that the acquisition of the laminin-binding capability is linked to the palindromic sequence LMWWML, which appeared during evolution concomitantly with laminin.
67千道尔顿层粘连蛋白受体（67LR）是一种非整合素细胞表面受体，介导细胞与层粘连蛋白之间的高亲和力相互作用。该蛋白在肿瘤细胞中的过表达与肿瘤侵袭和转移有关。迄今为止，仅分离出了编码37千道尔顿前体蛋白（37LRP）的全长基因。37LRP的cDNA与编码核糖体蛋白p40的cDNA几乎相同这一发现表明，37LRP实际上是翻译机制的一个组成部分，不具有层粘连蛋白结合活性。另一方面，从37LR/p40序列推导的一个20个氨基酸的肽段显示出高的层粘连蛋白结合活性。分析了37LRP/p40蛋白的23个序列之间的进化关系。这种系统发育分析表明，所有的蛋白质序列都来自直系同源基因，并且37LRP确实是一种核糖体蛋白，在进化过程中获得了层粘连蛋白受体的新功能。对人类蛋白质中被确定为层粘连蛋白结合位点的序列进行的进化分析表明，层粘连蛋白结合能力的获得与回文序列LMWWML有关，该序列在进化过程中与层粘连蛋白同时出现。
