Rickettsia Sca2 Recruits Two Actin Subunits for Nucleation but Lacks WH2 Domains.

ABSTRACT: The Rickettsia ∼1800-amino-acid autotransporter protein surface cell antigen 2 (Sca2) promotes actin polymerization on the surface of the bacterium to drive its movement using an actin comet-tail mechanism. Sca2 mimics eukaryotic formins in that it promotes both actin filament nucleation and elongation and competes with capping protein to generate filaments that are long and unbranched. However, despite these functional similarities, Sca2 is structurally unrelated to eukaryotic formins and achieves these functions through an entirely different mechanism. Thus, while formins are dimeric, Sca2 functions as a monomer. However, Sca2 displays intramolecular interactions and functional cooperativity between its N- and C-terminal domains that are crucial for actin nucleation and elongation. Here,

SUBMITTER: Alqassim SS 

PROVIDER: S-EPMC6369429 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature