Coordination of actin plus-end dynamics by IQGAP1, formin, and capping protein.
J Cell Biol
; 223(9)2024 Sep 02.
Article
en En
| MEDLINE
| ID: mdl-38787349
ABSTRACT
Cell processes require precise regulation of actin polymerization that is mediated by plus-end regulatory proteins. Detailed mechanisms that explain plus-end dynamics involve regulators with opposing roles, including factors that enhance assembly, e.g., the formin mDia1, and others that stop growth (capping protein, CP). We explore IQGAP1's roles in regulating actin filament plus-ends and the consequences of perturbing its activity in cells. We confirm that IQGAP1 pauses elongation and interacts with plus ends through two residues (C756 and C781). We directly visualize the dynamic interplay between IQGAP1 and mDia1, revealing that IQGAP1 displaces the formin to influence actin assembly. Using four-color TIRF, we show that IQGAP1's displacement activity extends to formin-CP "decision complexes," promoting end-binding protein turnover at plus-ends. Loss of IQGAP1 or its plus-end activities disrupts morphology and migration, emphasizing its essential role. These results reveal a new role for IQGAP1 in promoting protein turnover on filament ends and provide new insights into how plus-end actin assembly is regulated in cells.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Citoesqueleto de Actina
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Proteínas Activadoras de ras GTPasa
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Proteínas de Capping de la Actina
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Forminas
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Cell Biol
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos