ARGININE DEIMINASE PLAYS MULTIPLE REGULATORY ROLES IN THE BIOLOGY OF GIARDIA LAMBLIA

TOUZ MC; ROPOLO AS; RIVERO MR; VRANYCH CV; CONRAD JT; SVARD S; NASH TE

JOURNAL OF CELL SCIENCE

The Company of Biologists Ltd

Lugar: Cambridge, ; Año: 2008 vol. 121 p. 2930 - 2938

0021-9533

The early branching eukaryote Giardia lamblia utilize arginine deiminase (gADI) to produce energy from free L-arginine under anaerobic conditions. Conversely, higher eukaryotes use nitric oxide synthase to convert free L-arginine into L-citrulline and nitric oxide, and peptidyl-arginine deiminase to covert protein-bound arginine into citrulline. Here, we demonstrate that gADI binds specifically to the variant-specific surface protein (VSP) CRGKA cytoplasmic tail to produce post-translational citrullination of VSPs. This modification directly controls the VSP switching involved in the process of antigenic variation and cell survival. Additionally, during differentiation, gADI seems to play a regulatory role on the expression of encystation specific genes. Our findings reveal multiple physiological roles played by gADI and define novel regulatory pathways utilized by Giardia for survival.