Olofsson A, Ichijo H, Morén A, ten Dijke P, Miyazono K, Heldin C H
Ludwig Institute for Cancer Research, Biomedical Center, Uppsala, Sweden.
J Biol Chem. 1995 Dec 29;270(52):31294-7. doi: 10.1074/jbc.270.52.31294.
Latent transforming growth factor-beta (TGF-beta) binding protein-1 (LTBP-1) is a component of the high molecular weight latent TGF-beta complex found in various cells, including human platelets. LTBP-1 is observed as different molecular sizes in different cell types, probably due to proteolytic processing and alternative splicing. We here report a novel form of human LTBP-1, which is longer in its NH2-terminal part (LTBP-1L). Northern hybridization analysis revealed that the LTBP-1L is derived from a 7.0-kilobase mRNA, whereas the originally reported shorter form (LTBP-1S) is derived from a 5.2-kilobase mRNA. Transfection of cDNA for LTBP-1L and -1S in COS cells revealed that LTBP-1L bound more efficiently to the extracellular matrix than did LTBP-1S. These results suggest that the different splice forms of LTBP-1 mediate different localization patterns of the latent TGF-beta complexes in vivo.
潜伏转化生长因子-β（TGF-β）结合蛋白-1（LTBP-1）是在包括人血小板在内的各种细胞中发现的高分子量潜伏TGF-β复合物的一个组成部分。在不同细胞类型中，LTBP-1表现为不同的分子大小，这可能是由于蛋白水解加工和可变剪接所致。我们在此报告一种新型的人LTBP-1，其氨基末端部分更长（LTBP-1L）。Northern杂交分析显示，LTBP-1L源自一个7.0千碱基的mRNA，而最初报道的较短形式（LTBP-1S）源自一个5.2千碱基的mRNA。将LTBP-1L和-1S的cDNA转染到COS细胞中显示，LTBP-1L比LTBP-1S更有效地结合细胞外基质。这些结果表明，LTBP-1的不同剪接形式在体内介导潜伏TGF-β复合物的不同定位模式。
