Effect of D-serine on spermatogenesis and extracellular signal-regulated protein kinase (ERK) phosphorylation in the testis of the silkworm, Bombyx mori.
Effect of D-serine on spermatogenesis and extracellular signal-regulated protein kinase (ERK) phosphorylation in the testis of the silkworm, Bombyx mori.
复制标题
D-丝氨酸对家蚕睾丸精子发生和细胞外信号调节蛋白激酶 (ERK) 磷酸化的影响。
DOI：
10.1016/j.jinsphys.2014.06.003
复制
发表时间：
2014
期刊：
影响因子：
2.2
通讯作者：
Nagata Y.
中科院分区：
文献类型：
--
作者：
Suzuki C;Tanigawa M;Tanaka H;Horiike K;Kanekatsu R;Tojo M;Nagata Y.
尽管家蚕的蛹和幼虫含有特别大量的游离丝氨酸，但该氨基酸在家蚕中的生理作用尚不清楚。我们研究了 d-丝氨酸对精子发生的影响。整个幼虫发育过程中丝氨酸水平降低导致精子发生延迟，并导致丁芘精子数量减少。在第3天五龄幼虫的睾丸中，给予d-丝氨酸短暂地增加了细胞外信号调节蛋白激酶1/2（ERK1/2；以下简称ERK）的活化约25%。l-丝氨酸对ERK活化没有影响，并且其他器官对d-丝氨酸没有反应。通过施用 d-丝氨酸脱水酶（一种特异性降解 d-丝氨酸的酶）和该酶的抑制剂羟胺，证实了 d-丝氨酸对 ERK 激活的影响。睾丸中的 ERK 磷酸化分别被蛋白激酶 C (PKC) 和有丝分裂原相关蛋白激酶激酶 1/2 (MEK) 抑制剂 Go6983 和 U0126 显着抑制，但不被蛋白激酶 A (PKA) 抑制剂 H-89 抑制，表明睾丸中 ERK 通过 PKC 和 MEK 而不是通过 PKA 激活。 Go6983 或 U0126 对 ERK 磷酸化的抑制作用减少了 20-30% byd-丝氨酸。添加 d-丝氨酸后，抑制位点 (Ser259) 的 c-Raf 磷酸化减少了大约 30%。这些结果表明，d-丝氨酸通过包括 c-Raf 但不包括 PKC 或 MEK 的途径激活蚕睾丸中的 ERK。免疫组织化学证实了睾丸中丝氨酸诱导的 ERK 磷酸化，并揭示了精母细胞和精子细胞核中磷酸化 ERK 的存在。
Although the pupae and larvae ofBombyx moripossess especially large amounts of freed-serine, the physiological role of the amino acid in the silkworm is unknown. We investigated the effect ofd-serine on spermatogenesis. A loweredd-serine level throughout larval development caused a delay in spermatogenesis and resulted in reduced numbers of eupyrene sperm. Administration ofd-serine transiently increased the activation of extracellular signal-regulated protein kinase1/2 (ERK1/2; hereafter, ERK) by approximately 25% in the testis of day 3 fifth instar larvae.l-Serine had no effect on ERK activation, and other organs did not respond tod-serine. The effect ofd-serine on ERK activation was confirmed by administeringd-serine dehydratase, an enzyme that specifically degradesd-serine, and the enzyme’s inhibitor, hydroxylamine. ERK phosphorylation in the testis was significantly inhibited by Go6983 and U0126, inhibitors of protein kinase C (PKC) and mitogen-associated protein kinase kinase 1/2 (MEK), respectively, but not by H-89, a protein kinase A (PKA) inhibitor, indicating that ERK was activated in the testis via PKC and MEK but not via PKA. The inhibition of ERK phosphorylation by Go6983 or U0126 was reduced by 20–30% byd-serine. Roughly 30% of c-Raf phosphorylation at an inhibitory site (Ser259) was decreased by the addition ofd-serine. These results suggest thatd-serine activates ERK in the testis of silkworms through a pathway including c-Raf but not PKC or MEK. Immunohistochemistry confirmedd-serine-induced ERK phosphorylation in the testis and revealed the presence of phospho-ERK in the nuclei of spermatocytes and spermatids.