Perturbation of the interactions of calmodulin with GRK5 using a natural product chemical probe
- Univ. of Michigan, Ann Arbor, MI (United States)
- Purdue Univ., West Lafayette, IN (United States)
- Temple Univ., Philadelphia, PA (United States)
- Colorado State Univ., Fort Collins, CO (United States)
G protein-coupled receptor (GPCR) kinases (GRKs) are responsible for initiating desensitization of activated GPCRs. GRK5 is potently inhibited by the calcium-sensing protein calmodulin (CaM), which leads to nuclear translocation of GRK5 and promotion of cardiac hypertrophy. In this paper, we report the architecture of the Ca2+·CaM– GRK5 complex determined by small-angle X-ray scattering and negative-stain electron microscopy. Ca2+·CaM binds primarily to the small lobe of the kinase domain of GRK5 near elements critical for receptor interaction and membrane association, thereby inhibiting receptor phosphorylation while activating the kinase for phosphorylation of soluble substrates. To define the role of each lobe of Ca2+·CaM, we utilized the natural product malbrancheamide as a chemical probe to show that the C-terminal lobe of Ca2+·CaM regulates membrane binding while the N-terminal lobe regulates receptor phosphorylation and kinase domain activation. In cells, malbrancheamide attenuated GRK5 nuclear translocation and effectively blocked the hypertrophic response, demonstrating the utility of this natural product and its derivatives in probing Ca2+·CaM-dependent hypertrophy.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- National Institutes of Health (NIH); US Department of Education; Rackham Predoctoral Fellowship; Hans W. Vahlteich Professorship; Walther Cancer Foundation; LSI Cubed; USDOE Office of Science (SC); National Institute of General Medical Sciences (NIGMS); Michigan Economic Development Corporation and Michigan Technology Tri-Corridor
- Grant/Contract Number:
- HL071818; HL122416; CA221289; CA70375; R35 GM118101; AC02-06CH11357; 1S10OD018090-01; 085P1000817
- OSTI ID:
- 1557319
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 116, Issue 32; ISSN 0027-8424
- Publisher:
- National Academy of SciencesCopyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
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