scholarly journals The Role of Trs65 in the Ypt/Rab Guanine Nucleotide Exchange Factor Function of the TRAPP II Complex

2007 ◽  
Vol 18 (7) ◽  
pp. 2533-2541 ◽  
Author(s):  
Yongheng Liang ◽  
Nadya Morozova ◽  
Andrei A. Tokarev ◽  
Jonathan W. Mulholland ◽  
Nava Segev
Keyword(s):  
Intracellular Trafficking ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Cell Wall Biogenesis ◽  
Nucleotide Exchange Factor ◽  
Low Levels ◽  
Mutant Cells ◽  
Factor Function

The conserved modular complex TRAPP is a guanine nucleotide exchanger (GEF) for the yeast Golgi Ypt-GTPase gatekeepers. TRAPP I and TRAPP II share seven subunits and act as GEFs for Ypt1 and Ypt31/32, respectively, which in turn regulate transport into and out of the Golgi. Trs65/Kre11 is one of three TRAPP II-specific subunits. Unlike the other two subunits, Trs120 and Trs130, Trs65 is not essential for viability, is conserved only among some fungi, and its contribution to TRAPP II function is unclear. Here, we provide genetic, biochemical, and cellular evidence for the role of Trs65 in TRAPP II function. First, like Trs130, Trs65 localizes to the trans-Golgi. Second, TRS65 interacts genetically with TRS120 and TRS130. Third, Trs65 interacts physically with Trs120 and Trs130. Finally, trs65 mutant cells have low levels of Trs130 protein, and they are defective in the GEF activity of TRAPP II and the intracellular distribution of Ypt1 and Ypt31/32. Together, these results show that Trs65 plays a role in the Ypt GEF activity of TRAPP II in concert with the two other TRAPP II-specific subunits. Elucidation of the role played by Trs65 in intracellular trafficking is important for understanding how this process is coordinated with two other processes in which Trs65 is implicated: cell wall biogenesis and stress response.

scholarly journals LET-413/Erbin acts as a RAB-5 effector to promote RAB-10 activation during endocytic recycling

2017 ◽  
Vol 217 (1) ◽  
pp. 299-314 ◽  
Author(s):  
Hang Liu ◽  
Shimin Wang ◽  
Weijian Hang ◽  
Jinghu Gao ◽  
Wenjuan Zhang ◽  
...  
Keyword(s):  
Interacting Proteins ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Endocytic Recycling ◽  
Binding Partner ◽  
C Elegans ◽  
Intestinal Epithelia ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

RAB-10/Rab10 is a master regulator of endocytic recycling in epithelial cells. To better understand the regulation of RAB-10 activity, we sought to identify RAB-10(GDP)–interacting proteins. One novel RAB-10(GDP)–binding partner that we identified, LET-413, is the Caenorhabditis elegans homologue of Scrib/Erbin. Here, we focus on the mechanistic role of LET-413 in the regulation of RAB-10 within the C. elegans intestine. We show that LET-413 is a RAB-5 effector and colocalizes with RAB-10 on endosomes, and the overlap of LET-413 with RAB-10 is RAB-5 dependent. Notably, LET-413 enhances the interaction of DENN-4 with RAB-10(GDP) and promotes DENN-4 guanine nucleotide exchange factor activity toward RAB-10. Loss of LET-413 leads to cytosolic dispersion of the RAB-10 effectors TBC-2 and CNT-1. Finally, we demonstrate that the loss of RAB-10 or LET-413 results in abnormal overextensions of lateral membrane. Hence, our studies indicate that LET-413 is required for DENN-4–mediated RAB-10 activation, and the LET-413–assisted RAB-5 to RAB-10 cascade contributes to the integrity of C. elegans intestinal epithelia.

scholarly journals The role of VAV guanine nucleotide exchange factor in Dectin‐1 mediated phagocytosis

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Jill Kathleen Johnstone ◽  
Nicole A Morin ◽  
William G Cioffi ◽  
Jonathan S Reichner
Keyword(s):  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor
Sign in / Sign up

Export Citation Format

Share Document