Integration of linear and dendritic actin nucleation in Nck-induced actin comets

• Autores: Surtayeva, Sofya; Velle, Katrina B.; Campellone, Kenneth G.; Talman, Arthur; Alvarez, Diego Ezequiel; Agaisse, Hervé; Wu, Yi I.; Loew, Leslie M.; Mayer, Bruce J.
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: NUCLEATION PROMOTING FACTOR; SRC HOMOLOGY 3; VACCINIA VIRUS; FORMIN
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The Nck adaptor protein recruits cytosolic effectors such as N-WASP that induce localized actin polymerization. Experimental aggregation of Nck SH3 domains at the membrane induces actin comet tails-dynamic, elongated filamentous actin structures similar to those that drive the movement of microbial pathogens such as vaccinia virus. Here we show that experimental manipulation of the balance between unbranched/branched nucleation altered the morphology and dynamics of Nck-induced actin comets. Inhibition of linear, form-in-based nucleation with the small-molecule inhibitor SMIFH2 or overexpression of the formin FH1 domain resulted in formation of predominantly circular-shaped actin structures with low mobility (actin blobs). These results indicate that formin-based linear actin polymerization is critical for the formation and maintenance of Nck-dependent actin comet tails. Consistent with this, aggregation of an exclusively branched nucleation-promoting factor (the VCA domain of N-WASP), with density and turnover similar to those of N-WASP in Nck comets, did not reconstitute dynamic, elongated actin comets. Furthermore, enhancement of branched Arp2/3-mediated nucleation by N-WASP overexpression caused loss of the typical actin comet tail shape induced by Nck aggregation. Thus the ratio of linear to dendritic nucleation activity may serve to distinguish the properties of actin structures induced by various viral and bacterial pathogens.
Fil: Surtayeva, Sofya. University of Connecticut School of Medicine; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Velle, Katrina B.. University of Connecticut; Estados Unidos
Fil: Campellone, Kenneth G.. University of Connecticut; Estados Unidos
Fil: Talman, Arthur. Yale School of Medicine; Estados Unidos
Fil: Alvarez, Diego Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina
Fil: Agaisse, Hervé. Yale School of Medicine; Estados Unidos
Fil: Wu, Yi I.. University of Connecticut School of Medicine; Estados Unidos
Fil: Loew, Leslie M.. University of Connecticut School of Medicine; Estados Unidos
Fil: Mayer, Bruce J.. University of Connecticut School of Medicine; Estados Unidos