Reconstitution of Arp2/3-nucleated actin assembly with proteins CP, V-1, and CARMIL.

Autor:	Mooren OL; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA., McConnell P; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA., DeBrecht JD; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA., Jaysingh A; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA., Cooper JA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA. Electronic address: jcooper11@gmail.com.
Jazyk:	angličtina
Zdroj:	Current biology : CB [Curr Biol] 2024 Nov 18; Vol. 34 (22), pp. 5173-5186.e4. Date of Electronic Publication: 2024 Oct 21.
DOI:	10.1016/j.cub.2024.09.051
Abstrakt:	Actin polymerization is often associated with membrane proteins containing capping-protein-interacting (CPI) motifs, such as capping protein, Arp2/3, myosin I linker (CARMIL), CD2AP, and WASHCAP/Fam21. CPI motifs bind directly to actin-capping protein (CP), and this interaction weakens the binding of CP to barbed ends of actin filaments, lessening the ability of CP to functionally cap those ends. The protein V-1/myotrophin binds to the F-actin-binding site on CP and sterically blocks CP from binding barbed ends. CPI-motif proteins also weaken the binding between V-1 and CP, which decreases the inhibitory effects of V-1, thereby freeing CP to cap barbed ends. Here, we address the question of whether CPI-motif proteins on a surface analogous to a membrane lead to net activation or inhibition of actin assembly nucleated by Arp2/3 complex. Using reconstitution with purified components, we discovered that CARMIL at the surface promotes and enhances actin assembly, countering the inhibitory effects of V-1 and thus activating CP. The reconstitution involves the presence of an Arp2/3 activator on the surface, along with Arp2/3 complex, V-1, CP, profilin, and actin monomers in solution, recreating key features of cell physiology. Competing Interests: Declaration of interests The authors declare no conflict of interests. (Copyright © 2024 Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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