The maize abscisic acid (ABA)-responsive rab17 mRNA and Rab17 protein distribution in maize embryo tissues was investigated by in situ hybridization and immunocytochemistry. rab17 mRNA and Rab17 protein were found in all cells of embryo tissues. Synthesis of rab17 mRNA occurred initially in the embryo axis. As maturation progressed, rab17 mRNA was detectable in the scutellum and accumulated in ...

The small GTPase, Ras-related protein 17 (Rab17), a member of the Rab family, plays a critical role in the regulation of membrane traffic in polarized eukaryotic cells. However, the role of Rab17 in hepatocellular carcinoma (HCC) is not clear. Clinical speciments reveal that Rab17 was present in 15 of 20 (75.0%) paraneoplastic tissues and 7 of 20 (35.0%) HCC samples (P=0.0248). To elucidate the...

The rab subfamily of small GTPases has been demonstrated to play an important role in the regulation of membrane traffic in eukaryotic cells. Compared with nonpolarized cells, epithelial cells have distinct apical and basolateral transport pathways which need to be separately regulated. This raises the question whether epithelial cells require specific rab proteins. However, all rab proteins id...

The maize abscisic acid responsive protein Rab17 is a highly phosphorylated late embryogenesis abundant protein involved in plant responses to stress. In this study, we provide evidence of the importance of Rab17 phosphorylation by protein kinase CK2 in growth-related processes under stress conditions. We show the specific interaction of Rab17 with the CK2 regulatory subunits CK2 beta-1 and CK2...

A key feature of polarized epithelial cells is the ability to maintain the specific biochemical composition of the apical and basolateral plasma membrane domains while selectively allowing transport of proteins and lipids from one pole to the opposite by transcytosis. The small GTPase, rab17, a member of the rab family of regulators of intracellular transport, is specifically induced during cel...

We have previously shown that Rab17, a small GTPase associated with epithelial polarity, is specifically suppressed by ERK2 (also known as MAPK1) signalling to promote an invasive phenotype. However, the mechanisms through which Rab17 loss permits invasiveness, and the endosomal cargoes that are responsible for mediating this, are unknown. Using quantitative mass spectrometry-based proteomics, ...

Rab family small GTPases function as molecular switches in the regulation of membrane traffic, and their activity is thought to be controlled by guanine nucleotide exchange factors (GEFs). However, the role of GEFs in targeting Rab proteins to specific membrane compartments is poorly understood. We have recently reported finding that Rabex-5, originally described as a Rab5-GEF, also functions a...

Background: Small GTPase Rab17 regulates dendritic morphogenesis of hippocampal neurons, but its activation mechanism is completely unknown. Results: Expression of Rabex-5 in mouse hippocampal neurons promoted dendritic localization of Rab17, and Rabex-5 knockdown resulted in inhibition of neurite morphogenesis. Conclusion: Rabex-5 regulates neurite morphogenesis by activating Rab5 and Rab17. S...

Phylogenetic analysis of sequences from gene families and homologous genes from species of varying divergence can be used to identify conserved noncoding regulatory elements. In this study, phylogenetic analysis of 5'-noncoding sequences was optimized using rab17, a well-characterized ABA-responsive gene from maize, and five additional rab16/17 homologs from sorghum and rice. Conserved 5'-nonco...