Kalirin/Trio Rho guanine nucleotide exchange factors regulate a novel step in secretory granule maturation.

ABSTRACT: The molecular mechanisms involved in the maturation of secretory granules, organelles that store hormones and neuropeptides, are poorly understood. As granule content proteins are processed, the composition of granule membranes changes, yielding constitutive-like secretion of immature content proteins and producing secretagogue-responsive mature granules. Constitutive-like secretion was not previously recognized as a process subject to regulation. We show that Kalirin and Trio, homologous Rho guanine nucleotide exchange factors (GEFs), which interact with a secretory granule resident protein, modulate cargo secretion from immature granules. Some of the Kalirin and Trio isoforms expressed in neuroendocrine cells colocalize with immature granules. Overexpression of their N-terminal GEF domai

SUBMITTER: Ferraro F 

PROVIDER: S-EPMC2096607 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature