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bioRxiv · 10.1101/2023.05.01.538990

GPCR binding and JNK3 activation by arrestin-3 have different structural requirements

Zheng, C.·Weinstein, L. D.·Nguyen, K. K.·Grewal, A.·Gurevich, E. V.·Gurevich, V. V.
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Abstract

Arrestins bind active phosphorylated G protein-coupled receptors (GPCRs). Among the four mammalian subtypes, only arrestin-3 facilitates the activation of JNK3 in cells. In available structures, Lys-295 in the lariat loop of arrestin-3 and its homologue Lys-294 in arrestin-2 directly interact with the activator-attached phosphates. We compared the role of arrestin-3 conformational equilibrium and of Lys-295 in GPCR binding and JNK3 activation. Several mutants with enhanced ability to bind GPCRs showed much lower activity towards JNK3, whereas a mutant that does not bind GPCRs was more active. Subcellular distribution of mutants did not correlate with GPCR recruitment or JNK3 activation. Charge neutralization and reversal mutations of Lys-295 differentially affected receptor binding on different backgrounds, but had virtually no effect on JNK3 activation. Thus, GPCR binding and arrestin-3-assisted JNK3 activation have distinct structural requirements, suggesting that facilitation of JNK3 activation is the function of arrestin-3 that is not bound to a GPCR.

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Zheng, C., Weinstein, L. D., Nguyen, K. K., Grewal, A., Gurevich, E. V., Gurevich, V. V.. 2023-05-01. GPCR binding and JNK3 activation by arrestin-3 have different structural requirements. https://doi.org/10.1101/2023.05.01.538990

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