Ascorbate inducible N259 glycans on prolyl 4-hydroxylase subunit α1 promote hydroxylation and secretion of type I collagen
Ascorbate inducible N259 glycans on prolyl 4-hydroxylase subunit α1 promote hydroxylation and secretion of type I collagen
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脯氨酰 4-羟化酶亚基 α 1 上的抗坏血酸诱导型 N259 聚糖可促进 I 型胶原蛋白的羟基化和分泌
DOI：
10.1007/s00018-019-03081-w
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发表时间：
2019-09-01
影响因子：
8
通讯作者：
Li, Chaoyang
中科院分区：
文献类型：
--
作者：
Shi, Run;Hu, Weimin;Li, Chaoyang
抗坏血酸（维生素C，VC）通过促进脯氨酰4-羟化酶亚基α 1（P4 HA 1）的活性来增加成熟胶原蛋白的分泌。为了探索所涉及的机制，我们研究了N-连接糖基化的作用，它可以调节酶的活性。P4 HA 1具有两个糖基化位点，Asn（N）113和N259。我们的研究表明，N259的糖基化，而不是N113，由STT 3B和镁转运蛋白1（MAGT 1）增强VC。P4 HA 1上的N259糖基化与增强的胃蛋白酶抗性胶原1 α 2分泌相关。Stt 3b和Magt 1的下调减少P4 HA 1上的N259聚糖。在从Stt 3b沉默的成纤维细胞纯化的胶原1 α 2中，在5个特定的脯氨酸残基处发现羟基化降低，而在2个脯氨酸残基处注意到羟基化显著增加。类似地，在胶原1 α 1中，在8个位点检测到脯氨酸羟基化减少，在4个位点发现脯氨酸羟基化增加。这些结果表明，N-连接的糖基化的P4 HA 1可以直接羟基化在特定的脯氨酸残基和影响胶原成熟。
Ascorbic acid (vitamin C, VC) increases the secretion of mature collagen by promoting the activity of prolyl 4-hydroxylase subunit alpha 1 (P4HA1). To explore the mechanism involved, we investigated the role of N-linked glycosylation, which can regulate enzyme activity. P4HA1 has two glycosylation sites, Asn (N) 113 and N259. Our studies show that glycosylation of N259, but not N113, by STT3B and magnesium transporter 1 (MAGT1) is augmented by VC. N259 glycosylation on P4HA1 correlates with enhanced pepsin-resistant collagen 1 alpha 2 secretion. Downregulation of Stt3b and Magt1 reduces N259 glycans on P4HA1. In collagen 1 alpha 2 purified from Stt3b-silenced fibroblasts, decreased hydroxylation is found at five specific proline residues, while significantly increased hydroxylation is noted at two proline residues. Similarly, in collagen 1 alpha 1, reduced proline hydroxylation is detected at eight sites and increased proline hydroxylation is found at four sites. These results suggest that N-linked glycosylation of P4HA1 can direct hydroxylation at specific proline residues and affect collagen maturation.