Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase in cGMP metabolism in rabbit parotid acinar cells
Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase in cGMP metabolism in rabbit parotid acinar cells
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DOI：
10.2220/biomedres.27.37
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发表时间：
2006-02
影响因子：
1.2
通讯作者：
Nakayasu Sairenji;Keitaro Satoh;H. Sugiya
中科院分区：
文献类型：
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作者：
Nakayasu Sairenji;Keitaro Satoh;H. Sugiya
M胆碱能受体激活可刺激腮腺腺泡细胞中cGMP的形成。我们研究了钙/钙调蛋白依赖的环核苷酸磷酸二酯酶(PDE1)在兔腮腺腺泡细胞cGMP降解中的作用。M受体激动剂卡巴胆碱可刺激细胞内cGMP的形成。PDE1抑制剂8-甲氧甲基-3-异丁基-1-甲基黄嘌呤(MM-IBMX)可促进卡巴胆碱诱导的cGMP形成。在无钙/钙调素或MM-IBMX存在的情况下，兔腮腺腺泡细胞cGMPPDE活性降低约25%。用钙调素-Sepharose4B和Mono-Q离子交换柱层析纯化兔腮腺腺泡细胞钙/钙调素依赖性cGMP-PDE。两个具有cGMP-PDE活性的主要组分，称为P-1和P-2组分，从Mono Q离子交换柱上洗脱出来。P-1和P-2组分的cGMP的Km值分别为0.82μM和0.40μM，明显低于cAMP。P-1和P-2组分PDE对钙离子和钙调蛋白的EC50分别为458 nM和426 nM，32 nM和137 nM。检测到与抗PDE1A抗体发生交叉反应的蛋白条带。这些结果提示，钙/钙调蛋白依赖的PDE(PDE1a)参与了兔腮腺腺泡细胞cGMP的降解。
Muscarinic cholinergic receptor activation provokes cGMP formation in parotid acinar cells. We investigated the involvement of Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) in cGMP breakdown in rabbit parotid acinar cells. The muscarinic agonist carbachol stimulated cGMP formation in the cells. The carbachol-induced cGMP formation was enhanced in the presence of 8-methoxymethyl-3-isobutyl-1-methylxanthine (MM-IBMX), a PDE1 inhibitor. cGMPPDE activity in rabbit parotid acinar cells was reduced by about 25% in the absence of Ca2+/ calmodulin or in the presence of MM-IBMX. Ca2+/calmodulin-dependent cGMP-PDE in rabbit parotid acinar cells was purified using Calmodulin-Sepharose 4B and Mono Q ion-exchange column chromatography. Two dominant fractions with cGMP-PDE activity, referred to as the P-1 and P-2 fractions, were eluted from the Mono Q ion-exchange column. The Km values for cGMP of PDE in the P-1 and P-2 fractions were 0.82 μM and 0.40 μM, respectively, which were much lower than that for cAMP. The EC50 for Ca2+ and calmodulin of PDEs in the P-1 and P-2 fractions were 458 nM and 426 nM, respectively, and 32 nM and 137 nM, respectively. Protein bands that crossreacted with anti-PDE1A antibody were detected. These results suggest that Ca2+/calmodulin-dependent PDE, PDE1A, is involved in cGMP breakdown in rabbit parotid acinar cells.