Subcellular localization of the small GTPase Rab5a in resting and stimulated human neutrophils.
The evidence that small GTPases of the Rab family are regulators of vesicle traffic which can influence various cell functions prompted us to investigate the potential role of one of these proteins, Rab5a, in human neutrophils. In this paper we show that a large amount of Rab5a is present in the cytosol of peripheral blood mature neutrophils. The remaining protein was found to be membrane and azurophilic granule associated. Upon neutrophil challenge with PMA for 10 min the amount of membrane-associated Rab5a was upregulated while the cytosolic content of the protein concomitantly decreased. These findings support the hypothesis that Rab5a could be involved in the mechanism of neutrophil activation by modulating the rate of endocytosis and/or vesicle fusion.
Vita
F
F
Institute of General Pathology, University of Trieste, Italy.
Soranzo
M R
MR
Borelli
V
V
Bertoncin
P
P
Zabucchi
G
G
D003594:Cytoplasmic Granules / Q000737:chemistry / Q000201:enzymology; D003600:Cytosol / Q000737:chemistry / Q000201:enzymology; D020558:GTP Phosphohydrolases / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation / Q000502:physiology; D008565:Membrane Proteins / Q000032:analysis; D008854:Microscopy, Electron; D009504:Neutrophils / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D013347:Subcellular Fractions / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020696:rab5 GTP-Binding Proteins
D008565:Membrane Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate