title: How Rab proteins determine Golgi structure.
abstract: Rab proteins, small GTPases, are key regulators of mammalian Golgi apparatus organization. Based on the effect of Rab activation state, Rab proteins fall into two functional classes. In Class1, inactivation induces Golgi ribbon fragmentation and/or redistribution of Golgi enzymes to the Endoplasmic Reticulum, while overexpression of wild type or activation has little, if any, effect on Golgi ribbon organization. In Class 2, the reverse is true. We give emphasis to Rab6, the most abundant Golgi-associated Rab protein. Rab6 depletion in HeLa cells causes an increase in Golgi cisternal number, longer, more continuous cisternae, and a pronounced accumulation of vesicles; the effect of Rab6 on Golgi ribbon organization is probably through regulation of vesicle transport. In effector studies, motor proteins and their regulators are found to be key Rab6 effectors. A related Rab, Rab41, affects Golgi ribbon organization in a contrasting manner. The balance between minus- and plus-end directed motor recruitment may well be the major Rab-dependent factor in Golgi ribbon organization.
authors.affiliation: Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Shijie
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Storrie
mesh_terms: D000818:Animals; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D010641:Phenotype; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D020691:rab GTP-Binding Proteins
keywords: Golgi apparatus; Golgi ribbon organization; Rab41; Rab6; Rab6 subfamily