Evidence for multiple distinctly localized adenylyl cyclase isoforms in mammalian spermatozoa
Evidence for multiple distinctly localized adenylyl cyclase isoforms in mammalian spermatozoa
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DOI：
10.1002/mrd.10344
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发表时间：
2003-10-01
影响因子：
2.5
通讯作者：
Fraser, LR
中科院分区：
文献类型：
--
作者：
Baxendale, RW;Fraser, LR
除了碳酸氢盐调节的可溶性腺苷酸环化酶（sAC），哺乳动物精子，像体细胞，似乎含有受体/G蛋白调节的AC活性，有助于专门的细胞过程的调制。这项研究提供的证据表明，已知影响体细胞膜相关AC（mAC），但显然不是生殖细胞sAC的药物，可以调节小鼠精子中cAMP的产生和功能状态。具体而言，毛喉素显着增强cAMP的生产和获能，而包括2 '，5'-双脱氧腺苷显着阻断这些反应。此外，GTP γ S和NaF刺激cAMP，但GDP β S和mastoparan没有明显的作用，这与最近的证据一致，即G（s）而不是G（i）有助于非获能细胞中AC/cAMP的调节。此外，使用市售特异性抗体，通过免疫定位筛选完整小鼠精子中所有已知的mAC亚型。最丰富的亚型似乎是AC 2，AC 3和AC 8，每个在顶体和鞭毛区域有不同的分布; AC 1和AC 4也似乎存在，虽然不太丰富，在中段和顶体帽区域，分别。然而，有趣的是，Western blotting显示小鼠精子裂解物中的主要免疫反应蛋白比它们的体细胞对应物小得多（类似于50 -60 kDa），这表明成熟精子含有多个可能以缩短形式起作用的mAC。特别令人感兴趣的是AC 3和AC 8，它们位于与特异性细胞表面受体和G蛋白相同的区域，因此可能与它们直接相关，所述特异性细胞表面受体和G蛋白能够通过AC/cAMP的变化来调节精子的获得和维持可交配性。(C)2003 Wiley-Liss，Inc.
In addition to a bicarbonate-regulated soluble adenylyl cyclase (sAC), mammalian spermatozoa, like somatic cells, appear to contain receptor/G protein-regulated AC activity that contributes to the modulation of specialized cell processes. This study provides evidence that agents, known to influence somatic membrane-associated AC (mAC) but apparently not germ cell sAC, can modulate cAMP production and functional state in mouse spermatozoa. Specifically, forskolin significantly enhanced cAMP production and capacitation, while inclusion of 2',5'-dideoxyadenosine significantly blocked these responses. Furthermore, GTPgammaS and NaF stimulated cAMP, but GDPbetaS and mastoparan had no apparent effect, consistent with recent evidence that G(s), but not G(i), contributes to AC/cAMP regulation in uncapacitated cells. In addition, intact mouse spermatozoa were screened for all known mAC isoforms by immunolocalization, using commercially available specific antibodies. The most abundant isoforms appeared to be AC2, AC3, and AC8, each with distinct distributions in the acrosomal and flagellar regions; AC1 and AC4 also appeared to be present, although less abundantly, in the midpiece and acrosomal cap regions, respectively. Intriguingly, however, Western blotting revealed that the major immunoreactive proteins in mouse sperm lysates were considerably smaller (similar to50-60 kDa) than their somatic cell counterparts, suggesting that mature spermatozoa contain multiple mACs which may function in a shortened form. Of particular interest were AC3 and AC8, located in the same regions as, and hence possibly directly associated with, specific cell surface receptors and G proteins that are able to regulate the spermatozoon's acquisition and maintenance of fertilizing ability via changes in AC/cAMP. (C) 2003 Wiley-Liss, Inc.