title: γ-Tubulin localizes at actin-based membrane protrusions and inhibits formation of stress-fibers.
abstract: γ-Tubulin serves as a template in the γ-TuRC machinery to nucleate microtubules. Curiously, γ-tubulin also interacts with Arp2/3, a complex that nucleates actin filaments, and with the Arp2/3 activator WASH. We previously reported that γ-tubulin and Arp2/3 colocalize at the centrosome, where WASH localizes. Here, we report that γ-tubulin localizes at actin-based membrane protrusions, where Arp2/3 operates. This was confirmed by the presence of tagged γ-tubulin at membrane protrusions in stimulated cells and by downregulation of γ-tubulin expression. Surprisingly, expression of tagged γ-tubulin dramatically inhibited the formation of stress-fibers, while having no effect on microtubules. This phenotype is similar to the disruption of stress-fibers by the overexpression of the WCA domain of WASH and other Wiskott-Aldrich syndrome (WAS) family members. We hypothesize that γ-tubulin regulates Arp2/3 and actin nucleation promoting factors such as WASH, explaining the similar effect of γ-tubulin expression and WCA domain expression on stress-fibers. The data presented here indicate that γ-tubulin has a profound relationship with actin filament dynamics.
authors.affiliation: Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hubert
authors.forename: Sofie
authors.initials: S
authors.lastname: Perdu
authors.forename: Joël
authors.initials: J
authors.lastname: Vandekerckhove
authors.forename: Jan
authors.initials: J
authors.lastname: Gettemans
mesh_terms: D051377:Actin-Related Protein 2 / Q000378:metabolism; D051378:Actin-Related Protein 3 / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D045744:Cell Line, Tumor; D006367:HeLa Cells; D006801:Humans; D022502:Stress Fibers / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D014404:Tubulin