title: Rab27 and its effectors in secretory granule exocytosis: a novel docking machinery composed of a Rab27.effector complex.
abstract: A small GTPase Rab27 is present on secretory granules in a wide variety of secretory cells and on melanosomes in melanocytes, and it is involved in controlling the trafficking of these organelles through interaction with a cell-type- or tissue-specific Rab27 effector(s). Slps (synaptotagmin-like proteins) and rabphilin contain an N-terminal Rab27-binding domain and C-terminal tandem C2 domains, and some of the Rab27-binding proteins have recently been shown to promote docking of Rab27-bound organelles to the plasma membrane. This mini-review presents a model for how the Rab27.effector complex controls the docking step in the trafficking of Rab27-bound organelles. Our results indicate that Slp2-a, Slp4-a/granuphilin-a and rabphilin are capable of interacting with the plasma membrane directly or indirectly, and thus that these Rab27 effectors form a bridge between Rab27-bound organelles and the plasma membrane.
authors.affiliation: Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. nori@mail.tains.tohoku.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D003594:Cytoplasmic Granules / Q000502:physiology; D005089:Exocytosis / Q000502:physiology*; D016716:PC12 Cells; D010673:Pheochromocytoma; D051381:Rats; D022142:Secretory Vesicles / Q000502:physiology*; D033921:Vesicular Transport Proteins / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000502:physiology*; D000075745:rab27 GTP-Binding Proteins
chemical_list: D033921:Vesicular Transport Proteins; D000075745:rab27 GTP-Binding Proteins; C512961:Rab27a protein, rat; D020691:rab GTP-Binding Proteins