The Two Non-Visual Arrestins Engage ERK2 Differently

• Published in: Journal of molecular biology 2022-04, Vol.434 (7), p.167465-167465, Article 167465
• Main Authors: Perry-Hauser, Nicole A., Hopkins, Jesse B., Zhuo, Ya, Zheng, Chen, Perez, Ivette, Schultz, Kathryn M., Vishnivetskiy, Sergey A., Kaya, Ali I., Sharma, Pankaj, Dalby, Kevin N., Chung, Ka Young, Klug, Candice S., Gurevich, Vsevolod V., Iverson, T.M.
• Format: Article
• Language: English
• Subjects: arrestin; beta-Arrestin 1 - chemistry; beta-Arrestin 2 - chemistry; extracellular signal-regulated kinase 2; Mitogen-Activated Protein Kinase 1 - chemistry; Protein Binding; protein scaffolds; protein–protein interactions; Scattering, Small Angle; small-angle X-ray scattering; X-Ray Diffraction
• ISSN: 0022-2836; 1089-8638
• DOI: 10.1016/j.jmb.2022.167465

[Display omitted] •Non-visual arrestins act as scaffolds for signaling cascades, including ERK1/2.•Free arrestins form a binary pre-complex with ERK1/2.•Purified arrestin-2 and -3 bind purified ERK2 differently in binary complexes.•The ERK2 interaction with arrestin can be modulated using arrestin-2/3 chimeras.•Small-angle X-ray scattering suggests flexibility of the arrestin-3-ERK2 complex. Arrestin binding to active phosphorylated G protein-coupled receptors terminates G protein coupling and initiates another wave of signaling. Among the effectors that bind directly to receptor-associated arrestins are extracellular signal-regulated kinases 1/2 (ERK1/2), which promote cellular proliferation and survival. Arrestins may also engage ERK1/2 in isolation in a pre- or post-signaling complex that is likely in equilibrium with the full signal initiation complex. Molecular details of these binary complexes remain unknown. Here, we investigate the molecular mechanisms whereby arrestin-2 and arrestin-3 (a.k.a. β-arrestin1 and β-arrestin2, respectively) engage ERK1/2 in pairwise interactions. We find that purified arrestin-3 binds ERK2 more avidly than arrestin-2. A combination of biophysical techniques and peptide array analysis demonstrates that the molecular basis in this difference of binding strength is that the two non-visual arrestins bind ERK2 via different parts of the molecule. We propose a structural model of the ERK2-arrestin-3 complex in solution using size-exclusion chromatography coupled to small angle X-ray scattering (SEC-SAXS). This binary complex exhibits conformational heterogeneity. We speculate that this drives the equilibrium either toward the full signaling complex with receptor-bound arrestin at the membrane or toward full dissociation in the cytoplasm. As ERK1/2 regulates cell migration, proliferation, and survival, understanding complexes that relate to its activation could be exploited to control cell fate.