Sarkar Parijat, Bhat Akrati, Chattopadhyay Amitabha
CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India.
J Membr Biol. 2022 Dec;255(6):739-746. doi: 10.1007/s00232-022-00262-w. Epub 2022 Aug 20.
G protein-coupled receptors (GPCRs) constitute the largest class of membrane proteins that transduce signals across the plasma membrane and orchestrate a multitude of physiological processes within cells. The serotonin receptor is a crucial neurotransmitter receptor in the GPCR family involved in a multitude of neurological, behavioral and cognitive functions. We have previously shown, using a combination of experimental and simulation approaches, that membrane cholesterol acts as a key regulator of organization, dynamics, signaling and endocytosis of the serotonin receptor. In addition, we showed that membrane cholesterol stabilizes the serotonin receptor against thermal deactivation. In the present work, we explored the molecular basis of cholesterol-induced thermal stability of the serotonin receptor. For this, we explored the possible role of the K101 residue in a cholesterol recognition/interaction amino acid consensus (CRAC) motif in transmembrane helix 2 in conferring the thermal stability of the serotonin receptor. Our results show that a mutation in the K101 residue leads to loss in thermal stability of the serotonin receptor imparted by cholesterol, independent of membrane cholesterol content. We envision that our results could have potential implications in structural biological advancements of GPCRs and design of thermally stabilized receptors for drug development.
G蛋白偶联受体（GPCRs）是最大的一类膜蛋白，可跨质膜转导信号并协调细胞内众多生理过程。血清素受体是GPCR家族中一种关键的神经递质受体，参与多种神经、行为和认知功能。我们之前使用实验和模拟方法相结合的方式表明，膜胆固醇是血清素受体组织、动力学、信号传导和内吞作用的关键调节因子。此外，我们还表明膜胆固醇可稳定血清素受体，使其免受热失活影响。在本研究中，我们探索了胆固醇诱导血清素受体热稳定性的分子基础。为此，我们研究了跨膜螺旋2中胆固醇识别/相互作用氨基酸共识（CRAC）基序中的K101残基在赋予血清素受体热稳定性方面可能发挥的作用。我们的结果表明，K101残基的突变会导致胆固醇赋予的血清素受体热稳定性丧失，且与膜胆固醇含量无关。我们设想我们的结果可能对GPCRs的结构生物学进展以及用于药物开发的热稳定受体设计具有潜在意义。
