Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan.
Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, 351-0198, Japan.
Biochem Biophys Res Commun. 2021 Jun 30;560:93-98. doi: 10.1016/j.bbrc.2021.04.128. Epub 2021 May 10.
Glucosyl-galactosyl-hydroxylation (GGH) is one type of post-translational modification, which is mainly observed in collagen-like domain-containing proteins. Using LC-MS/MS analysis, we found a GGH-like modification at Lys65 of fibrinogen-like protein 1 (FGL1), although it does not contain a collagen-like domain. To identify the glycosyltransferases responsible for this modification, we established LH3/GLT25D1-knockout FGL1-overexpressing HT1080 cell lines. The result showed that knockout of LH3 or GLT25D1 significantly inhibited the glycosylation. Furthermore, deficiency of GGH by point mutation of the FGL1 protein or knockout of the GGH-related glycosyltransferase reduced FGL1 protein levels. Taken together, these data indicate that Lys65 of FGL1 is glucosyl-galactosyl-hydroxylated by LH3 and GLT25D1. Our results provide novel insights to regulate various FGL1 functions.
糖基化-半乳糖基化-羟化（GGH）是一种翻译后修饰，主要发生在含有胶原样结构域的蛋白质中。我们通过 LC-MS/MS 分析，在纤维蛋白原样蛋白 1（FGL1）的赖氨酸 65 位发现了一种 GGH 样修饰，尽管它不含有胶原样结构域。为了鉴定负责这种修饰的糖基转移酶，我们建立了 LH3/GLT25D1 敲除 FGL1 过表达 HT1080 细胞系。结果表明，LH3 或 GLT25D1 的敲除显著抑制了糖基化。此外，通过 FGL1 蛋白点突变或敲除 GGH 相关糖基转移酶来抑制 GGH，可降低 FGL1 蛋白水平。总之，这些数据表明 FGL1 的赖氨酸 65 位由 LH3 和 GLT25D1 进行糖基化-半乳糖基化-羟化。我们的研究结果为调节各种 FGL1 功能提供了新的思路。
