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

TOUZ MC, EQUAL CONTRIBUTOR; ROPOLO AS, EQUAL CONTRIBUTOR; RIVERO MR; VRANYCH, CV; CONRAD JT; SVARD SG; NASH TE

COMPANY OF BIOLOGISTS LTD

Año: 2008 vol. 121 p. 2930 - 2930

nbsp; The protozoan parasite Giardia lamblia utilizes arginine deiminase (gADI) to produce energy from free L-arginine under anaerobic conditions. In this work, we demonstrate that in addition to its known role as a metabolic enzyme, it also functions as a pepidtyl-arginine deiminase converting protein-bound arginine into citrulline. gADI specifically binds to and citrullinates the arginine in the conserved CRGKA tail of variant-specific surface proteins (VSPs) affecting both antigenic switching and antibody mediated cell death. During encystation gADI translocates from the cytoplasm to the nucleus and appear to play a regulatory role in the expression of encystation specific genes. gADI is also sumoylated, which may modulate its activity. Our findings reveal a dual role played by gADI and define novel regulatory pathways used by