College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
Liaoning General Fair Testing Company, Ltd, Shenyang 110026, China.
J Agric Food Chem. 2020 Apr 15;68(15):4546-4556. doi: 10.1021/acs.jafc.9b06850. Epub 2020 Apr 2.
Phosphorylation is a widespread posttranslational protein modification and is important in various biological processes. However, milk fat globule membrane (MFGM) phosphoproteins have not been explored systematically in human milk. Here, we used quantitative phosphoproteomics to analyze phosphorylation sites in human MFGM proteins and their differences at different stages of lactation; 305 phosphorylation sites on 170 proteins and 269 phosphorylation sites on 170 proteins were identified in colostrum and mature MFGM, respectively. Among these, 71 phosphorylation sites on 48 proteins were differentially expressed between the different stages of lactation. Osteopontin in human MFGM was the most heavily phosphorylated protein, with a total of 39 identified phosphorylation sites. Our results shed light on phosphorylation sites, composition, and biological functions of MFGM phosphoproteins in human colostrum and mature milk, and provide novel insights into the crucial roles of protein phosphorylation during infant development.
磷酸化是一种广泛存在的蛋白质翻译后修饰，在各种生物过程中都很重要。然而，人乳中的乳脂肪球膜（MFGM）磷酸化蛋白尚未得到系统研究。在这里，我们使用定量磷酸蛋白质组学分析了人乳 MFGM 蛋白中的磷酸化位点及其在泌乳不同阶段的差异；在初乳和成熟 MFGM 中分别鉴定出 170 种蛋白质上的 305 个磷酸化位点和 170 种蛋白质上的 269 个磷酸化位点。其中，48 种蛋白质上的 71 个磷酸化位点在泌乳不同阶段存在差异表达。人乳 MFGM 中的骨桥蛋白是磷酸化程度最高的蛋白质，共鉴定出 39 个磷酸化位点。我们的研究结果揭示了人乳初乳和成熟乳 MFGM 磷酸化蛋白的磷酸化位点、组成和生物学功能，为婴儿发育过程中蛋白质磷酸化的关键作用提供了新的见解。
