Substrate binding disrupts dimerization and induces nucleotide exchange of the chloroplast GTPase Toc33.

ABSTRACT: GTPases act as molecular switches to control many cellular processes, including signalling, protein translation and targeting. Switch activity can be regulated by external effector proteins or intrinsic properties, such as dimerization. The recognition and translocation of pre-proteins into chloroplasts [via the TOC/TIC (translocator at the outer envelope membrane of chloroplasts/inner envelope membrane of chloroplasts)] is controlled by two homologous receptor GTPases, Toc33 and Toc159, whose reversible dimerization is proposed to regulate translocation of incoming proteins in a GTP-dependent manner. Toc33 is a homodimerizing GTPase. Functional analysis suggests that homodimerization is a key step in the translocation process, the molecular functions of which, as well as the elements regu

SUBMITTER: Oreb M 

PROVIDER: S-EPMC4086448 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature