Luna C, Serrano E, Domingo J, Casao A, Pérez-Pé R, Cebrián-Pérez J A, Muiño-Blanco T
Facultad de Veterinaria, Departamento de Bioquímica y Biología Molecular y Celular, Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Zaragoza, Spain.
Facultad de Veterinaria, Departamento de Bioquímica y Biología Molecular y Celular, Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Zaragoza, Spain.
Theriogenology. 2016 Aug;86(3):704-14. doi: 10.1016/j.theriogenology.2016.02.024. Epub 2016 Mar 8.
Spermatozoa require substantially more ATP than other cells, not only for sustaining sperm motility but also for regulating protein phosphorylation during capacitation. In this study, we have reported for the first time the presence of the two key enzymes of the pentose phosphate pathway (PPP), glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in ovine spermatozoa by indirect immunofluorescence, Western blotting, in-gel activity, and reverse transcription polymerase chain reaction analysis. We found that the activity of both enzymes significantly increased after in vitro capacitation in the presence of high-cAMP levels, with a concomitant increase in protein tyrosine phosphorylation and in the proportion of sperm-capacitated pattern assessed by the chlortetracycline staining. These results suggest that PPP is related with the progress of capacitation and that a relationship between calcium compartmentalization, protein tyrosine phosphorylation and PPP seems to exist. This is the first report that shows a connection between the PPP, cAMP/PKA signaling pathways and sperm capacitation. These findings can be of high-biological importance to improve our knowledge of the biochemical mechanisms involved in the acquisition of mammalian sperm functional competence and, ultimately, fertility.
精子比其他细胞需要更多的三磷酸腺苷（ATP），这不仅是为了维持精子活力，也是为了在获能过程中调节蛋白质磷酸化。在本研究中，我们首次通过间接免疫荧光、蛋白质免疫印迹、凝胶内活性分析以及逆转录聚合酶链反应分析，报道了戊糖磷酸途径（PPP）的两种关键酶，即葡萄糖-6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶在绵羊精子中的存在。我们发现，在高环磷酸腺苷（cAMP）水平存在的情况下，体外获能后这两种酶的活性均显著增加，同时蛋白质酪氨酸磷酸化增加，并且通过金霉素染色评估的精子获能模式比例也增加。这些结果表明，PPP与获能过程相关，并且钙区室化、蛋白质酪氨酸磷酸化和PPP之间似乎存在关联。这是首次报道显示PPP、cAMP/蛋白激酶A（PKA）信号通路与精子获能之间存在联系。这些发现对于增进我们对哺乳动物精子功能能力获得以及最终生育能力所涉及的生化机制的了解可能具有高度生物学重要性。
