Suppression of adenylyl cyclase-mediated cAMP production by plasma membrane associated cytoskeletal protein 4.1G
Suppression of adenylyl cyclase-mediated cAMP production by plasma membrane associated cytoskeletal protein 4.1G
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DOI：
10.1016/j.cellsig.2012.11.020
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发表时间：
2013-03-01
影响因子：
4.8
通讯作者：
Nakahata, Norimichi
中科院分区：
文献类型：
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作者：
Goto, Toshihiro;Chiba, Ayano;Nakahata, Norimichi
最近的研究表明，G蛋白偶联受体(GPCRs)的活性受一系列与GPCRs的羧基(C)末端结合的蛋白质的调节。4.1家族蛋白是皮质下细胞骨架蛋白的亚类，具有稳定细胞结构和质膜蛋白的功能。4.1G是4.1家族蛋白之一，它与GPCRs的C末端相互作用，调节受体的细胞内分布，包括甲状旁腺激素(PTH)/甲状旁腺激素相关蛋白受体(PTHR)。甲状旁腺素受体与三聚体G蛋白G(S)和G(Q)偶联，分别激活腺苷环化酶/环磷酸腺苷(CAMP)途径和磷脂酶C途径。在研究4.1G对腺苷酸环化酶/cAMP信号通路的作用过程中，我们发现4.1G抑制了Forsklin诱导的细胞内cAMP的产生。在过度表达4.1G的HEK293细胞中，Forsklin诱导的cAMP积聚减少，而在4.1G-基因敲除的HEK293细胞中cAMP积聚增加。此外，PTH-(1-34)刺激的cAMP的产生在外源表达的4.1G的存在下也被抑制，尽管它有增加PTHR在细胞表面的分布的活性。在过量表达FERM结构域缺失的4.1G的细胞中，该蛋白的突变体形式在质膜分布上缺乏，无论是Forsklin诱导的还是PTH-(1-34)刺激的cAMP的产生都没有改变。即使在4.1G过表达细胞的膜制剂中也能观察到Forsklin诱导的cAMP生成受到抑制。在4.1G基因敲除的HEK293细胞中，该酶的主要亚型之一腺酰环化酶6的质膜分布略有减少，但在Forsklin刺激下，这些细胞内cAMP的生成增加。此外，细胞松弛素D对Forsklin诱导的HEK293细胞内cAMP的产生没有任何影响。这些数据表明，质膜相关的4.1G通过抑制腺酰环化酶介导的cAMP的产生来调节GPCR介导的Gs信号。(C)2012 Elsevier Inc.保留所有权利。
It has been shown lately that activity of G protein-coupled receptors (GPCRs) is regulated by an array of proteins binding to carboxy (C)-terminus of GPCRs. Proteins of 4.1 family are subsets of subcortical cytoskeletal proteins and are known to stabilize cellular structures and proteins at the plasma membrane. One of the 4.1 family proteins, 4.1G has been shown to interact with the C-terminus of GPCRs and regulate intracellular distribution of the receptors, including parathyroid hormone (PTH)/PTH-related protein receptor (PTHR). PTHR is coupled to trimeric G proteins G(s) and G(q), which activate the adenylyl cyclase/cyclic AMP (CAMP) pathway and phospholipase C pathway, respectively. During the course of investigation of the role of 4.1G on adenylyl cyclase/cAMP signaling pathway, we found that 4.1G suppressed forskolin-induced cAMP production in cells. The cAMP accumulation induced by forskolin was decreased in HEK293 cells overexpressing 4.1G or increased in 4.1G-knockdown cells. Furthermore, PTH -(1-34)-stimulated cAMP production was also suppressed in the presence of exogenously expressed 4.1G despite its activity to increase the distribution of PTHR to the cell surface. In cells overexpressing FERM domain-deleted 4.1G, a mutant form of the protein deficient in plasma membrane distribution, neither forskolin-induced nor PTH -(1-34)-stimulated cAMP production was not altered. The suppression of the forskolin-induced CAMP production was observed even in membrane preparations of 4.1G-overexpressing cells. In 4.1G-knockdown HEK293 cells, plasma membrane distribution of adenylyl cyclase 6, one of the major subtypes of the enzyme in the cells, showed a slight decrease, in spite of the increased production of cAMP in those cells when stimulated by forskolin. Also, cytochalasin D treatment did not cause any influence on forskolin-induced cAMP production in HEK293 cells. These data indicate that plasma membrane-associated 4.1G regulates GPCR-mediated Gs signaling by suppressing adenylyl cyclase-mediated cAMP production. (C) 2012 Elsevier Inc. All rights reserved.