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Guanine nucleotide exchange factor 2 for Rab5 proteins coordinated with GLUP6/GEF regulates the intracellular transport of the proglutelin from the Golgi apparatus to the protein storage vacuole in rice endosperm.

Wen L, Fukuda M, Sunada M, Ishino S, Ishino Y, Okita TW, Ogawa M, Ueda T, Kumamaru T - J. Exp. Bot. (2015)

Bottom Line: Like GLUP6/GEF, Rab5-GEF2 was capable of activating Rab5a and two other Rab5 isoforms in in vitro GTP/GDP exchange assays.GEF proteins consist of the helical bundle (HB) domain at the N-terminus, Vps9 domain, and a C-terminal region.By the deletion analysis of GEFs, the HB domain was found essential for the activation of Rab5 proteins.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan Tobacco Research Institute, Chinese Academy of Agricultural Science, Qingdao 266101, China.

No MeSH data available.


Related in: MedlinePlus

in vitro GEF assay of GLUP6/GEF. The conformational changes of Rab5s and Rab11 (as 1 μM GST fusion proteins) upon GDP/GMP-PNP exchange were measured by monitoring Trp autofluorescence when incubated with 0 μM (blue), 0.25 μM (magenta), 0.5 μM (yellow), and 1 μM (red) GST-GLUP6/GEF. Note that GST-GLUP6/GEF activates Rab5b and Rab5c, but not Rab11.
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Figure 5: in vitro GEF assay of GLUP6/GEF. The conformational changes of Rab5s and Rab11 (as 1 μM GST fusion proteins) upon GDP/GMP-PNP exchange were measured by monitoring Trp autofluorescence when incubated with 0 μM (blue), 0.25 μM (magenta), 0.5 μM (yellow), and 1 μM (red) GST-GLUP6/GEF. Note that GST-GLUP6/GEF activates Rab5b and Rab5c, but not Rab11.

Mentions: In order to elucidate whether the GLUP6/GEF can activate other Rab5s in rice, in vitro guanine nucleotide exchange assays using tryptophan autofluorescence were conducted using GST-tagged recombinant proteins as described previously (Fukuda et al., 2013). In this study, Rab5b and Rab5c were selected as representative of the plant-specific type and conventional type of Rab5 isoforms, respectively. As shown in Fig. 5, Rab5b and Rab5c were activated by GLUP6/GEF in a dose-dependent manner, whereas, in contrast, Rab11 was not activated by GLUP6/GEF. These results indicate that GLUP6/GEF activates not only GLUP4/Rab5a but also at least two other Rab5 isoforms present in developing rice endosperm. Evidence for the genetic and physical interactions of GLUP6/GEF to Rab5 family proteins was also reported by Liu et al. (2013). Overall, the collective evidence suggests that, in addition to GLUP4/Rab5a, other Rab5 isoforms such as Rab5b and Rab5c may participate in glutelin trafficking.


Guanine nucleotide exchange factor 2 for Rab5 proteins coordinated with GLUP6/GEF regulates the intracellular transport of the proglutelin from the Golgi apparatus to the protein storage vacuole in rice endosperm.

Wen L, Fukuda M, Sunada M, Ishino S, Ishino Y, Okita TW, Ogawa M, Ueda T, Kumamaru T - J. Exp. Bot. (2015)

in vitro GEF assay of GLUP6/GEF. The conformational changes of Rab5s and Rab11 (as 1 μM GST fusion proteins) upon GDP/GMP-PNP exchange were measured by monitoring Trp autofluorescence when incubated with 0 μM (blue), 0.25 μM (magenta), 0.5 μM (yellow), and 1 μM (red) GST-GLUP6/GEF. Note that GST-GLUP6/GEF activates Rab5b and Rab5c, but not Rab11.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588877&req=5

Figure 5: in vitro GEF assay of GLUP6/GEF. The conformational changes of Rab5s and Rab11 (as 1 μM GST fusion proteins) upon GDP/GMP-PNP exchange were measured by monitoring Trp autofluorescence when incubated with 0 μM (blue), 0.25 μM (magenta), 0.5 μM (yellow), and 1 μM (red) GST-GLUP6/GEF. Note that GST-GLUP6/GEF activates Rab5b and Rab5c, but not Rab11.
Mentions: In order to elucidate whether the GLUP6/GEF can activate other Rab5s in rice, in vitro guanine nucleotide exchange assays using tryptophan autofluorescence were conducted using GST-tagged recombinant proteins as described previously (Fukuda et al., 2013). In this study, Rab5b and Rab5c were selected as representative of the plant-specific type and conventional type of Rab5 isoforms, respectively. As shown in Fig. 5, Rab5b and Rab5c were activated by GLUP6/GEF in a dose-dependent manner, whereas, in contrast, Rab11 was not activated by GLUP6/GEF. These results indicate that GLUP6/GEF activates not only GLUP4/Rab5a but also at least two other Rab5 isoforms present in developing rice endosperm. Evidence for the genetic and physical interactions of GLUP6/GEF to Rab5 family proteins was also reported by Liu et al. (2013). Overall, the collective evidence suggests that, in addition to GLUP4/Rab5a, other Rab5 isoforms such as Rab5b and Rab5c may participate in glutelin trafficking.

Bottom Line: Like GLUP6/GEF, Rab5-GEF2 was capable of activating Rab5a and two other Rab5 isoforms in in vitro GTP/GDP exchange assays.GEF proteins consist of the helical bundle (HB) domain at the N-terminus, Vps9 domain, and a C-terminal region.By the deletion analysis of GEFs, the HB domain was found essential for the activation of Rab5 proteins.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan Tobacco Research Institute, Chinese Academy of Agricultural Science, Qingdao 266101, China.

No MeSH data available.


Related in: MedlinePlus