Signal recognition particle (SRP) and SRP receptor: a new paradigm for multistate regulatory GTPases.

ABSTRACT: The GTP-binding proteins or GTPases comprise a superfamily of proteins that provide molecular switches in numerous cellular processes. The "GTPase switch" paradigm, in which a GTPase acts as a bimodal switch that is turned "on" and "off" by external regulatory factors, has been used to interpret the regulatory mechanism of many GTPases for more than two decades. Nevertheless, recent work has unveiled an emerging class of "multistate" regulatory GTPases that do not adhere to this classical paradigm. Instead of relying on external nucleotide exchange factors or GTPase activating proteins to switch between the on and off states, these GTPases have the intrinsic ability to exchange nucleotides and to sense and respond to upstream and downstream factors. In contrast to the bimodal nature of the

SUBMITTER: Shan SO 

PROVIDER: S-EPMC2883566 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature