PRKAR1A and cystic fibrosis: Their pioneering work shows that the haemolysin co-regulated protein (Hcp) secretion island I-encoded T6SS of the bacterium Pseudomonas aeruginosa, a human pathogen of cystic fibrosis (CF) lung disease (Ratjen, 2009 ▶), targets at least three proteins, termed type VI secretion exported 1–3 (Tse1–Tse3), to the periplasmic space of rival bacteria (Hood et al., 2010 ▶).