Dimer-dependent intrinsic/basal activity of the class B G protein-coupled receptor PAC1 promotes cellular anti-apoptotic activity through Wnt/β-catenin pathways that are associated with dimer endocytosis.
Dimer-dependent intrinsic/basal activity of the class B G protein-coupled receptor PAC1 promotes cellular anti-apoptotic activity through Wnt/β-catenin pathways that are associated with dimer endocytosis.
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DOI：
10.1371/journal.pone.0113913
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Zhong J
中科院分区：
文献类型：
--
作者：
Yu R;Cui Z;Li M;Yang Y;Zhong J
垂体腺苷酸环化酶激活多肽（PACAP）偏好受体PAC 1的高表达与神经损伤和肿瘤有关。我们先前的报道（Yu R，et al.PLoS One 2012; 7：e51811）证实了PAC 1的二聚化，并发现N-末端第一个Cys/Ala中的M-PAC 1突变丧失了形成二聚体的能力。在这项研究中，中国仓鼠卵巢（CHO-K1）细胞过度表达野生型PAC1（PAC1-CHO）有显着更高的抗凋亡活性对血清撤药诱导的细胞凋亡与较低的caspase 3活性和较高的Bcl-2水平，在配体非依赖性的方式比CHO细胞过度表达突变体M-PAC1（M-PAC1-CHO）。与M-PAC 1-CHO相比，PAC 1-CHO具有显著更高的对应于Wnt/β-catenin信号的β-catenin、细胞周期蛋白D1和c-myc水平。Wnt/β-catenin通路抑制剂XAV 939可显著抑制PAC1-CHO的抗凋亡活性。顶闪测定表明，PAC1-CHO具有比M-PAC1-CHO显著更强的Wnt/β-连环蛋白信号。乙酰半胱氨酸（NAC）作为PAC 1二聚化的抑制剂，可抑制PAC 1赋予的抗凋亡活性，并降低Top-flash检测中Wnt/β-catenin信号。在多西环素（Dox）诱导的PAC1泰特（四环素）-on诱导基因表达系统中，PAC1表达水平越高，其抗凋亡活性越强，并伴随着更强的Wnt/β-catenin信号。在Neuro2a神经母细胞瘤细胞中也发现了与PAC 1下调类似的相关性。BiFC结合荧光共聚焦成像表明，在血清撤回诱导的细胞凋亡，PAC 1二聚体显示出显着的内吞作用。这些发现表明，PAC 1具有配体非依赖性和二聚体依赖性的内在/基础活性，赋予细胞抗血清戒断的抗凋亡活性，其参与Wnt/β-连环蛋白信号并与PAC 1二聚体的内吞作用相关。PAC1二聚体依赖性基础活性的发现和研究不仅有助于我们了解PAC1的生理和病理作用，而且有助于开发以PAC1为靶点的药物。
The high expression of PACAP (pituitary adenylate cyclase-activating polypeptide)-preferring receptor PAC1 is associated with nerve injury and tumors. Our previous report (Yu R, et al. PLoS One 2012; 7: e51811) confirmed the dimerization of PAC1 and found that the M-PAC1 mutation in the N-terminal first Cys/Ala lost the ability to form dimers. In this study, Chinese hamster ovary (CHO-K1) cells overexpressing wild-type PAC1 (PAC1-CHO) had significantly higher anti-apoptotic activities against serum withdrawal-induced apoptosis associated with a lower caspase 3 activity and a higher Bcl-2 level in a ligand-independent manner than those of CHO cells overexpressing the mutant M-PAC1 (M-PAC1-CHO). PAC1-CHO had significantly higher β-catenin, cyclin D1 and c-myc levels corresponding to the Wnt/β-catenin signal than did M-PAC1-CHO. In addition, the Wnt/β-catenin pathway inhibitor XAV939 significantly inhibited the anti-apoptotic activities of PAC1-CHO. Top-flash assays demonstrated that PAC1-CHO had a significantly stronger Wnt/β-catenin signal than did M-PAC1-CHO. Acetylcysteine (NAC) as an inhibitor of the dimerization of PAC1 inhibited the anti-apoptotic activities that were endowed by PAC1 and decreased the Wnt/β-catenin signal in Top-flash assays. In the PAC1 Tet (tetracycline)-on inducible gene expression system by doxycycline (Dox), higher expression levels of PAC1 resulted in higher anti-apoptotic activities that were associated with a stronger Wnt/β-catenin signal. A similar correlation was also found with the down-regulation of PAC1 in the Neuro2a neuroblastoma cell. BiFC combined with fluorescence confocal imaging indicated that during serum-withdrawal-induced apoptosis, PAC1 dimers displayed significant endocytosis. These findings indicate that PAC1 has ligand-independent and dimer-dependent intrinsic/basal activity, conferring cells with anti-apoptotic activities against serum withdrawal, which is involved in the Wnt/β-catenin signal and is associated with the endocytosis of PAC1 dimers. The discovery and study of the dimer-dependent basal activity of PAC1 not only help us understand the physiological and pathological role of PAC1 but also promote the development of drugs targeting PAC1.
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DOI：
10.1186/1756-9966-32-100
发表时间：
2013-12-05
期刊：
Journal of experimental & clinical cancer research : CR
影响因子：
--
作者：
Tian XH;Hou WJ;Fang Y;Fan J;Tong H;Bai SL;Chen Q;Xu H;Li Y
通讯作者：
Li Y
影响因子：
5.3
作者：
Kniazeff, J;Saintot, PP;Pin, JP
通讯作者：
Pin, JP
影响因子：
3.8
作者：
Cohen JR;Resnick DZ;Niewiadomski P;Dong H;Liau LM;Waschek JA
通讯作者：
Waschek JA
影响因子：
3.5
作者：
OKAZAKI, K;KIMURA, C;FUJINO, M
通讯作者：
FUJINO, M
影响因子：
15.9
作者：
Lang, Bing;Song, Bing;Shen, Sanbing
通讯作者：
Shen, Sanbing