介导鱼类孕激素快速、非基因作用的受体研究进展

许多研究发现某些孕激素受体介导的生物学反应较迅速,而经典的通过基因起作用的孕激素核受体介导的生物学反应都较慢,因此有学者提出生物体可能存在不通过基因起作用的孕激素受体,并研究了其结构和功能,探讨了其快速反应的机制。迄今为止,在鱼类已发现了3类可能的非基因作用的膜受体。第1类为孕激素脂联素受体家族(PAQR)的3个成员,即PAQR7(mPRα),PAQR8(mPRβ)和PAQR5(mPRγ),这些成员存在于多种硬骨鱼类中,具有和G蛋白偶联受体(GPCRs)相似的7次跨膜结构域。其中对mPRα和mPRβ的研究较多,它们可以诱导鱼类卵母细胞成熟和增强鱼类精子的活动性。第2类为孕酮受体膜组成部分(PGRMCs),是一类小分子蛋白。目前发现有PGMRC1和PGMRC2两种,对PGMRC1的研究较多,它的作用与mPRβ的作用相似,都参与孕酮的调节作用。第3类是孕激素核受体(nPRs),研究发现一些细胞中的孕激素核受体也能够参与介导孕激素的快速生物学反应。本文对介导鱼类非基因作用的孕激素受体在结构、功能和作用机制等方面的研究进展进行了介绍。

Advances in receptors for mediating rapid nongenomic progestin actions in fishes

Many rapid nongenomic actions have been identified in response to progestins,compared to the classical slow genomic actions.Accordingly,it was suggested that some nongenomic progestin receptors should exist and their components,functions and rapid responses have been investigated.Currently,three potential candidates of nongenomic membrane receptors have been found.The first one is the progestin and adiponectin receptors(PAQR),including PAQR7(mPRα),PAQR8(mPRβ)and PAQR5(mPRγ),which have seven integral transmembrane domains similar to those of the G protein-coupled receptors(GPCRs)in many species of teleost.Further investigations,focusing on the functions of mPRα and mPRβ,indicate that they are involved in the induction of oocyte maturation and the improvement of sperm motility.The second one is progesterone receptor membrane components(PGRMCs)composed of small molecular proteins.Studies focusing on the functions of PGRMC1 have found that they play a similar role as mPRβ does in the regulation of progesterone.The third potential candidate is nuclear progestin receptors(nPRs),which have been found to be involved in rapid nongenomic actions.However,the evidence for the existence of specific nongenomic membrane receptors remains controversial.The present paper summarizes the progress in the study of components,functions and mechanisms of nongenomie receptors in fishes.