Rac1 dynamics in the human opportunistic fungal pathogen Candida albicans.
The small Rho G-protein Rac1 is highly conserved from fungi to humans, with approximately 65% overall sequence identity in Candida albicans. As observed with human Rac1, we show that C. albicans Rac1 can accumulate in the nucleus, and fluorescence recovery after photobleaching (FRAP) together with fluorescence loss in photobleaching (FLIP) studies indicate that this Rho G-protein undergoes nucleo-cytoplasmic shuttling. Analyses of different chimeras revealed that nuclear accumulation of C. albicans Rac1 requires the NLS-motifs at its carboxyl-terminus, which are blocked by prenylation of the adjacent cysteine residue. Furthermore, we show that C. albicans Rac1 dynamics, both at the plasma membrane and in the nucleus, are dependent on its activation state and in particular that the inactive form accumulates faster in the nucleus. Heterologous expression of human Rac1 in C. albicans also results in nuclear accumulation, yet accumulation is more rapid than that of C. albicans Rac1. Taken together our results indicate that Rac1 nuclear accumulation is an inherent property of this G-protein and suggest that the requirements for its nucleo-cytoplasmic shuttling are conserved from fungi to humans.
Institute of Developmental Biology and Cancer, Centre National de la Recherche Scientifique UMR 6543, Université de Nice, Faculté des Sciences-Parc Valrose, Nice, France.
Romain
R
Vauchelles
Danièle
D
Stalder
Thomas
T
Botton
Robert A
RA
Arkowitz
Martine
M
Bassilana
D002176:Candida albicans / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
D020830:rac1 GTP-Binding Protein