Pharmaceutical Research Laboratories, Nippon Kayaku Co., Ltd, 3-31-12, Shimo, Kita-ku, Tokyo 115-0042, Japan.
Department of Chemistry and Life Science, School of Advanced Engineering, Kogakuin University, 2655-1, Nakanomachi, Hachioji city, Tokyo 192-0015, Japan.
J Biochem. 2018 Aug 1;164(2):173-181. doi: 10.1093/jb/mvy040.
Expression of type IV collagen α1 chain in non-triple helical form, NTH α1(IV), is observed in cultured human cells, human placenta and rabbit tissues. Biological functions of NTH α1(IV) are most likely to be distinct from type IV collagen, since their biochemical characteristics are quite different. To explore the biological functions of NTH α1(IV), we prepared some anti-NTH α1(IV) antibodies. In the course of characterization of these antibodies, one antibody, #141, bound to a polypeptide of 140 kDa in size in addition to NTH α1(IV). In this study, we show evidence that the 140 kDa polypeptide is a novel non-triple helical polypeptide of type VI collagen α1 chain encoded by COL6A1, or NTH α1(VI). Expression of NTH α1(VI) is observed in supernatants of several human cancer cell lines, suggesting that the NTH α1(VI) might be involved in tumourigenesis. Reactivity with lectins indicates that sugar chains of NTH α1(VI) are different from those of the α1(VI) chain in triple helical form of type VI collagen, suggesting a synthetic mechanism and a mode of action of NTH α1(VI) is different from type VI collagen.
非三螺旋形式的 IV 型胶原α1 链（NTHα1(IV)）在培养的人细胞、人胎盘和兔组织中被观察到。NTHα1(IV)的生物学功能很可能与 IV 型胶原不同，因为它们的生化特性有很大的不同。为了探索 NTHα1(IV)的生物学功能，我们制备了一些抗 NTHα1(IV)抗体。在这些抗体的特性研究过程中，一种抗体#141 除了与 NTHα1(IV)结合外，还与一种 140 kDa 的多肽结合。在本研究中，我们证明了该 140 kDa 多肽是一种新型的非三螺旋多肽，属于 COL6A1 编码的 VI 型胶原α1 链，即 NTHα1(VI)。NTHα1(VI)在几种人癌细胞系的上清液中表达，提示 NTHα1(VI)可能参与肿瘤发生。与凝集素的反应表明，NTHα1(VI)的糖链与 VI 型胶原三螺旋形式的α1(VI)链的糖链不同，提示 NTHα1(VI)的合成机制和作用方式不同于 VI 型胶原。
