The ADAM-integrin-tetraspanin complex in fetal and postnatal testicular cords.
The ADAM-integrin-tetraspanin complex in fetal and postnatal testicular cords.
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DOI：
10.1002/bdrc.20041
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发表时间：
2005-06-01
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影响因子：
--
通讯作者：
Kierszenbaum, Abraham L
中科院分区：
文献类型：
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作者：
Tres, Laura L;Kierszenbaum, Abraham L
在睾丸索形成过程中，出现了关于ADAM（一种去整合素和金属蛋白酶）结构域蛋白家族的表达的新见解，该蛋白家族结合了细胞表面粘附和蛋白水解活性;该家族包括整合素α 3 β 1和α 6 β 1以及四跨膜蛋白，这是一个独特的蛋白家族，包含四个跨膜结构域、一个小的和一个大的细胞外环以及短的细胞质尾。ADAM 3（cyritestin）、ADAM 5、ADAM 6和ADAM 15在胎鼠睾丸中表达。相反，在胎儿睾丸中未检测到ADAM 1/ADAM 2对（分别为受精素α/受精素β）的表达。然而，ADAM 1的表达在出生后立即开始，并在24小时内表达ADAM 2。因此，ADAM 1/ADAM 2异二聚体在精子发生的减数分裂和精子发生阶段之前就被观察到。观察到整合素亚基α 3、α 6和β 1以及四跨膜蛋白CD 9、CD 81和CD 98的类似表达模式;后者是一种单程整合素亚基β 1结合蛋白。在前精原细胞（也称为原始生殖细胞或生殖细胞）中观察到ADAM 2、整合素亚基α 3、α 6和β 1以及四跨膜蛋白CD 9和CD 81免疫反应位点。提出了一个模型，其中的ADAM-整合素-四跨膜蛋白复合物，已知构成一个网络的膜微域称为四跨膜蛋白网络，可能参与前精原细胞从中心到周边的睾丸索的迁移和在精子发生的初始波期间的有丝分裂活动的重新启动。一个互补的模型包括在重排的tetraspanin网络在prespermatogens/精原细胞进行自发或Fas诱导的凋亡后，与支持细胞共培养。在该模型中，参与凋亡前小体形成的细胞部位没有四跨膜蛋白-整合素簇，与非凋亡细胞相反，其显示弥漫性周向分布。在凋亡的前精原细胞中，免疫反应簇仅限于前精原细胞/精原细胞与支持细胞表面的附着仍然保留的部位。
New insights have emerged about the expression, during testicular cord formation, of the ADAM (a disintegrin and metalloprotease) domain family of proteins that combines both cell surface adhesion and proteolytic activity; this family includes integrins alpha3beta1 and alpha6beta1 and tetraspanins, a distinct family of proteins containing four transmembrane domains, a small and a large extracellular loop, and short cytoplasmic tails. ADAM3 (cyritestin), ADAM5, ADAM6, and ADAM15 are expressed in fetal rat testes. In contrast, the expression of the ADAM1/ADAM2 pair (fertilin alpha/fertilin beta, respectively) is not detected in fetal testis. Yet the expression of ADAM1 starts immediately after birth, and is followed within 24 hr by the expression of ADAM2. Therefore, the ADAM1/ADAM2 heterodimer is visualized far in advance of the meiotic and spermiogenic phase of spermatogenesis. A similar expression pattern was observed for integrin subunits alpha3, alpha6, and beta1, as well as for tetraspanins CD9, CD81, and CD98; the latter is a single-pass integrin subunit beta1-binding protein. ADAM2, integrin subunits alpha3, alpha6, and beta1, and tetraspanin CD9 and CD81 immunoreactive sites are observed in prespermatogonia (also known as primordial germ cells or gonocytes). A model is proposed in which the ADAM-integrin-tetraspanin complex, known to constitute a network of membrane microdomains called the tetraspanin web, may be involved in the migration of prespermatogonia from the center to the periphery of the testicular cords and in the reinitiation of mitotic activity during the initial wave of spermatogenesis. A complementary model consists in the rearrangement of the tetraspanin web in prespermatogonia/spermatogonia undergoing spontaneous or Fas-induced apoptosis upon coculturing with Sertoli cells. In this model, the cellular site involved in the formation of preapoptotic bodies is devoid of tetraspanin-integrin clusters, in contrast with nonapoptotic cells, which display a diffuse circumferential distribution. In apoptotic prespermatogonia, immunoreactive clusters are restricted to sites where the attachment of prespermatogonia/spermatogonia to Sertoli cell surfaces is still preserved.