Abstract 2462 Does the C-terminus of Bordetella's Fic protein influence GMPylation-mediated signal transduction?

Fic (Filamentation induced by cAMP) proteins constitute a family of enzymes that regulate cell signaling in bacteria and metazoans via post-translational modifications (PTMs). Predominant amongst these PTMs is AMPylation/adenylylation, whereby the Fic protein utilizes ATP to add an AMP moiety to its target. Here, we report the discovery of a highly conserved Fic protein from Bordetella sp. bacteria, which cause respiratory diseases including Whooping Cough in humans. Our studies with the Bordetella bronchiseptica Fic protein (BbFic) reveal that this clade of Fic proteins carries out a previously unseen PTM - specifically, BbFic functions as a guanlylyltransferase, catalyzing GTP to add a GMP on itself and its putative target(s).