This family consists of several Actinobacillus actinomycetemcomitans leukotoxin activator (LktC) proteins. Actinobacillus actinomycetemcomitans is a Gram-negative bacterium that has been implicated in the etiology of several forms of periodontitis, especially localised juvenile periodontitis. LktC along with LktB and LktD are thought to be required for activation and localisation of the leukotoxin [1].

1: Regulation of leukotoxin in leukotoxic and nonleukotoxic strains of Actinobacillus actinomycetemcomitans. Spitznagel J Jr, Kraig E, Kolodrubetz D; Infect Immun 1991;59:1394-1401. PMID:2004819