Regulates aggregation via a pathway that involves lagC and tgrD1/lagD. Inhibits lagC and activates lagD expression. Expressed from early development; required for aggregation prior to fruiting body formation and sporulation. Down-regulated by Pseudomonas aeruginosa, PAO1 strain and up-regulated by PA14 strain infection. Cells are unable to sporulate when in pure population although they will sporulate when in chimerae with wild-type cells. Cells form loose aggregate before disaggregating. Cells aggregate and disaggregate in waves. comC-/lagC-/tgrD1-mutant fails to form spores.