University of Denver, Department of Biological Sciences, Denver, CO 80210, USA.
University of Denver, Department of Biological Sciences, Denver, CO 80210, USA.
Gen Comp Endocrinol. 2020 Jul 1;293:113463. doi: 10.1016/j.ygcen.2020.113463. Epub 2020 Mar 22.
In the current study, the whale shark (ws; Rhincodon typus) melanocortin-2 receptor (MC2R) co-expressed with wsMRAP1 in Chinese Hamster Ovary (CHO) Cells could be stimulated in a dose dependent manner by ACTH(1-24) with an EC of 2.6 × 10 M ± 9.7 × 10. When the receptor was expressed alone, stimulation was only observed at [10 M]. A comparable increase in sensitivity to stimulation by srDes-Ac-αMSH was also observed when the receptor was co-expressed with wsMRAP1. In addition, co-expression with wsMRAP1 significantly increased the trafficking of wsMC2R to the plasma membrane of CHO cells. Surprisingly, co-expression with wsMRAP2 also increased sensitivity to stimulation by ACTH(1-24) and srDes-Ac-αMSH, and increased trafficking of the receptor to the plasma membrane. These observations are in sharp contrast to the response of MC2R orthologs of bony vertebrates which have an obligate requirement for co-expression with MRAP1 for both trafficking to the plasma membrane and activation, and while co-expression with MRAP2 increases trafficking, it has minimal effects on activation. In addition, when comparing the activation features of wsMC2R with those of the elephant shark MC2R and red stingray MC2R orthologs, both similarities and differences are observed. The spectrum of features for cartilaginous fish MC2R orthologs will be discussed. A second objective of this study was to determine whether wsMC5R has features in common with wsMC2R in terms of ligand selectivity and interaction with wsMRAP paralogs. While wsMC5R can be activated by either srACTH(1-24) or srDes-Ac-αMSH, and co-expression with wsMRAP1 enhances this activation, wsMRAP1 had no effect on the trafficking of wsMC5R. Co-expression with wsMRAP2 had no positive or negative effect on either ligand sensitivity or trafficking of wsMC5R.
在本研究中，中国仓鼠卵巢（CHO）细胞中与 wsMRAP1 共表达的鲸鲨（ws；Rhincodon typus）黑素皮质素-2 受体（MC2R）可被 ACTH（1-24）以剂量依赖的方式刺激，EC 为 2.6×10-9 M±9.7×10-10 M。当受体单独表达时，仅在 [10 M] 时观察到刺激。当受体与 wsMRAP1 共表达时，对 srDes-Ac-αMSH 刺激的敏感性也观察到类似的增加。此外，wsMRAP1 的共表达显著增加了 wsMC2R 向 CHO 细胞质膜的转运。令人惊讶的是，wsMRAP2 的共表达也增加了对 ACTH（1-24）和 srDes-Ac-αMSH 的刺激敏感性，并增加了受体向质膜的转运。这些观察结果与硬骨脊椎动物 MC2R 同系物的反应形成鲜明对比，后者对向质膜的转运和激活都需要与 MRAP1 共表达，而与 MRAP2 共表达增加了转运，但对激活的影响很小。此外，当比较 wsMC2R 与象鲨 MC2R 和红 stingray MC2R 同系物的激活特征时，观察到相似之处和差异。软骨鱼 MC2R 同系物的特征谱将进行讨论。本研究的第二个目的是确定 wsMC5R 在配体选择性和与 wsMRAP 同源物的相互作用方面是否与 wsMC2R 具有共同特征。虽然 wsMC5R 可被 srACTH（1-24）或 srDes-Ac-αMSH 激活，并且与 wsMRAP1 的共表达增强了这种激活，但 wsMRAP1 对 wsMC5R 的转运没有影响。wsMRAP2 的共表达对 wsMC5R 的配体敏感性或转运没有积极或消极的影响。
