The surface of the spermatozoa is coated with glycoproteins the redistribution of which during in vitro capacitation plays a key role in the subsequent fertilization process. Lipid rafts are membrane microdomains involved in signal transduction through receptors and include or recruit specific types of proteins and glycoproteins. Few studies have focused on identifying glycoproteins resident in the lipid rafts of spermatozoa. Proteins associated with lipid rafts modify their localization during capacitation. The objective of the study was to identify the glycoproteins associated with lipid rafts of capacitated boar spermatozoa through a lectin-binding assay coupled to mass spectrometry approach. From the proteomic profiles generated by the raft proteins extractions, we observed that after capacitation the intensity of some bands increased while that of others decreased. To determine whether the proteins obtained from lipid rafts are glycosylated, lectin blot assays were performed. Protein bands with a good resolution and showing significant glycosylation modifications after capacitation were analyzed by mass spectrometry. The bands of interest had an apparent molecular weight of 64, 45, 36, 34, 24, 18 and 15 kDa. We sequenced the 7 bands and 20 known or potential glycoproteins were identified. According to us, for ten of them this is the first time that their association with sperm lipid rafts is described (ADAM5, SPMI, SPACA1, Seminal plasma protein pB1, PSP-I, MFGE8, tACE, PGK2, SUCLA2, MDH1). Moreover, LYDP4, SPAM-1, HSP60, ZPBP1, AK1 were previously reported in lipid rafts of mouse and human spermatozoa but not in boar spermatozoa. We also found and confirmed the presence of ACR, ACRBP, AWN, AQN3 and PRDX5 in lipid rafts of boar spermatozoa. This paper provides an overview of the glycosylation pattern in lipid rafts of boar spermatozoa before and after capacitation. Further glycomic analysis is needed to determine the type and the variation of glycan chains of the lipid rafts glycoproteins on the surface of spermatozoa during capacitation and acrosome reaction.

中文翻译：

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从公猪精子中获得的脂筏糖蛋白的鉴定。

精子的表面涂有糖蛋白，在体外获能过程中糖蛋白的重新分布在随后的受精过程中起关键作用。脂筏是参与通过受体信号转导的膜微区，包括或募集特定类型的蛋白质和糖蛋白。很少有研究集中在鉴定精子脂质筏中的糖蛋白。与脂筏相关的蛋白质会在获能过程中改变其定位。该研究的目的是通过凝集素结合测定法和质谱法鉴定与获胜的公猪精子脂质筏相关的糖蛋白。从筏蛋白提取产生的蛋白质组学概况来看，我们观察到，获能后，某些谱带的强度增加，而另一些谱带的强度下降。为了确定从脂质筏获得的蛋白质是否被糖基化，进行了凝集素印迹测定。质谱分析了获能后具有良好分辨率并显示出明显糖基化修饰的蛋白条带。目的条带的表观分子量为64、45、36、34、24、18和15 kDa。我们对7条带进行了测序，鉴定了20种已知或潜在的糖蛋白。据我们介绍，这是其中十个首次描述它们与精子脂筏的关系（ADAM5，SPMI，SPACA1，精浆蛋白pB1，PSP-1，MFGE8，tACE，PGK2，SUCLA2，MDH1）。此外，LYDP4，SPAM-1，HSP60，ZPBP1，先前曾在小鼠和人类精子的脂质筏中报道了AK1，但在公猪精子中没有报道。我们还发现并确认了公猪精子脂质筏中存在ACR，ACRBP，AWN，AQN3和PRDX5。本文概述了获能前后公猪精子脂质筏中的糖基化模式。需要进一步的糖类分析以确定在获能和顶体反应过程中精子表面脂筏糖蛋白的聚糖链的类型和变异。