Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vesicle traffic between the endoplasmic reticulum and the Golgi apparatus in mammals requires the small GTP-binding protein Rab2, but Saccharomyces cerevisiae appears not to have a Rab2 homolog. Here it is shown that the higher plant, Arabidopsis thaliana, contains a gene, At-RAB2, whose predicted product shares 79% identity with human Rab2 protein. Transgenic plants containing fusions between beta-glucuronidase and sequences upstream of At-RAB2 demonstrated histochemical staining predominantly in maturing pollen and rapidly growing organs of germinating seedlings. beta-glucuronidase activity in pollen is first detectable at microspore mitosis and increases thereafter. In this respect, the promoter of At-RAB2 behaves like those of class II pollen-specific genes, whose products are often required after germination for pollen tube growth. Seedling germination and pollen tube growth are notable for their unusually high rates of cell wall and membrane biosynthesis. These results are consistent with a role for At-RAB2 in secretory activity.
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PMID:A homolog of the mammalian GTPase Rab2 is present in Arabidopsis and is expressed predominantly in pollen grains and seedlings. 901 59

Ran-binding proteins (RanBPs) are a group of proteins that bind to Ran (Ras-related nuclear small GTP-binding protein), and thus either control the GTP/GDP-bound states of Ran or help couple the Ran GTPase cycle to a cellular process. AtRanBP1c is a Ran-binding protein from Arabidopsis thaliana (L.) Heynh. that was recently shown to be critically involved in the regulation of auxin-induced mitotic progression [S.-H. Kim et al. (2001) Plant Cell 13:2619-2630]. Here we report that AtRanBP1c inhibits the EDTA-induced release of GTP from Ran and serves as a co-activator of Ran-GTPase-activating protein (RanGAP) in vitro. Transient expression of AtRanBP1c fused to a beta-glucuronidase (GUS) reporter reveals that the protein localizes primarily to the cytosol. Neither the N- nor C-terminus of AtRanBP1c, which flank the Ran-binding domain (RanBD), is necessary for the binding of PsRan1-GTP to the protein, but both are needed for the cytosolic localization of GUS-fused AtRanBP1c. These findings, together with a previous report that AtRanBP1c is critically involved in root growth and development, imply that the promotion of GTP hydrolysis by the Ran/RanGAP/AtRanBP1c complex in the cytoplasm, and the resulting concentration gradient of Ran-GDP to Ran-GTP across the nuclear membrane could be important in the regulation of auxin-induced mitotic progression in root tips of A. thaliana.
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PMID:An Arabidopsis Ran-binding protein, AtRanBP1c, is a co-activator of Ran GTPase-activating protein and requires the C-terminus for its cytoplasmic localization. 1268 74

OsRab5a encodes a Rab5 protein in rice, which belongs to the Rab family of small GTP-binding protein superfamily. Transgenic plants with POsrab5a::beta-glucuronidase (GUS) gene indicate that OsRab5a is expressed in callus, root, stem, leaf, root base and spikelet (Figs.1, 2H-1). Using the transgenic Arabidopsis with fused gene of GFP::OsRab5a and GFP::OsRab5aCA and by using FM4-64 (the lipophilic styryl dye) staining, we have demonstrated that OsRab5a is involved in vesicular transport and GFP-OsRab5a is localized on the plasma membrane and early endosomes (Fig.2A-C), while GFP-OsRab5aCA is localized in the cell membrane (Fig.2D-F). The reduction of expression of OsRab5a in callus RNA interference, however, led to the lethality of callus during differentiation (Fig.3D-F). The expression of OsRab5a was upregulated slightly by exogenous cytokinin (Fig.4), and was higher in the differentiation medium than that in selection medium (Fig.3G-I). These results suggest that OsRab5a plays an important role in callus differentiation probably through mediating hormone signal transduction.
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PMID:[A preliminary analysis of the function of the OsRab5a gene in rice (Oryza sativa L.)]. 1647 29