Faculty Opinions recommendation of REI-1 Is a Guanine Nucleotide Exchange Factor Regulating RAB-11 Localization and Function in C. elegans Embryos.

Author(s):  
Mitsunori Fukuda
2015 ◽  
Vol 35 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Aisa Sakaguchi ◽  
Miyuki Sato ◽  
Katsuya Sato ◽  
Keiko Gengyo-Ando ◽  
Tomohiro Yorimitsu ◽  
...  

Cell ◽  
2005 ◽  
Vol 123 (1) ◽  
pp. 119-132 ◽  
Author(s):  
Kenneth R. Norman ◽  
Robert T. Fazzio ◽  
Jerry E. Mellem ◽  
Maria V. Espelt ◽  
Kevin Strange ◽  
...  

2016 ◽  
Vol 310 (6) ◽  
pp. C456-C469 ◽  
Author(s):  
Jay M. Bhatt ◽  
Ekaterina G. Viktorova ◽  
Theodore Busby ◽  
Paulina Wyrozumska ◽  
Laura E. Newman ◽  
...  

Members of the large Sec7 domain-containing Arf guanine nucleotide exchange factor (GEF) family have been shown to dimerize through their NH2-terminal dimerization and cyclophilin binding (DCB) and homology upstream of Sec7 (HUS) domains. However, the importance of dimerization in GEF localization and function has not been assessed. We generated a GBF1 mutant (91/130) in which two residues required for oligomerization (K91 and E130 within the DCB domain) were replaced with A and assessed the effects of these mutations on GBF1 localization and cellular functions. We show that 91/130 is compromised in oligomerization but that it targets to the Golgi in a manner indistinguishable from wild-type GBF1 and that it rapidly exchanges between the cytosolic and membrane-bound pools. The 91/130 mutant appears active as it integrates within the functional network at the Golgi, supports Arf activation and COPI recruitment, and sustains Golgi homeostasis and cargo secretion when provided as a sole copy of functional GBF1 in cells. In addition, like wild-type GBF1, the 91/130 mutant supports poliovirus RNA replication, a process requiring GBF1 but believed to be independent of GBF1 catalytic activity. However, oligomerization appears to stabilize GBF1 in cells, and the 91/130 mutant is degraded faster than the wild-type GBF1. Our data support a model in which oligomerization is not a key regulator of GBF1 activity but impacts its function by regulating the cellular levels of GBF1.


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