Secreted Proteases Control the Timing of Aggregative Community Formation in Vibrio cholerae

Abstract

Bacteria can work as collectives to form multicellular communities. Vibrio cholerae , the bacterium that causes the disease cholera in humans, forms aggregated communities in liquid. Aggregate formation relies on a chemical communication process called quorum sensing.

Proteases influence colony aggregation behavior in Vibrio cholerae

“…The vca081 2 and vca0813 genes are located adjacent to one another in an operon on the V. cholerae chromosome and encode the multidomain proteins LapX (Uniprot KB Q9KLD4) and Lap (Lap, Uniprot, KB: Q9KLD3; EC 3.4.11.10), respectively ( 15 ) ( Fig. 1 , A and B ).…”

“…1 A ). Previous work showed that while LapX and Lap are required for V. cholerae aggregation, GbpA is not ( 15 ); hence we focus here on LapX and Lap. LapX is a leucine aminopeptidase-related protein, a putative serine protease that belongs to the subfamily A of the S1 family of the PA clan proteases.…”

“…In V. cholerae , four proteases are involved in the liquid-based aggregation program: HapA, PrtV, LapX, and Lap ( 15 ). All four proteases are secreted.…”

“…All four proteases are secreted. A mutant V. cholerae strain lacking all four proteases displays a greater delay in the onset of the aggregation phenotype than a mutant lacking only Lap and LapX ( 15 ) (all further mentions of Lap and LapX refer to the V. cholerae proteins). HapA and PrtV are known to have other roles in Vibrio biology, including degradation of mucin during invasion ( 16 ), proteolysis of host proteins ( 17 ), and degradation of GbpA ( 18 ), a polysaccharide monooxygenase involved in both mucin binding and chitin oxidation ( 19 , 20 ).…”

“…HapA and PrtV are known to have other roles in Vibrio biology, including degradation of mucin during invasion ( 16 ), proteolysis of host proteins ( 17 ), and degradation of GbpA ( 18 ), a polysaccharide monooxygenase involved in both mucin binding and chitin oxidation ( 19 , 20 ). However, involvement in aggregation is the first and only identified physiological role for LapX and Lap and represents a new molecular mechanism underlying posttranslational regulation of bacterial aggregation ( 4 , 15 ).…”