Table 1.

Pilotins and accessory molecules of the T2SS, T3SS, and T4PS

System	Pilotin	Accessory molecule	Cognate secretin	Bacterial species	Main references
T2SS	EpsS	EpsA EpsB	EpsD	Vibrio vulnificus	Howard et al. 15 Strozen et al.55
	AspS		GspD	Escherichia coli (EPEC)	Dunstan et al.38 Yin et al.36
	AspS		GspD	Vibrio cholerae	Dunstan et al.38
	OutS		OutD	Erwinia chrysanthemi	Rehman et al.61
	PulS		PulD	Klebsiella oxytoca	Tosi et al.33 Nickerson et al.34
		ExeA ExeB	ExeD	Aeromonas hydrophila	Li and Howard62 Ast et al.63 Vanderlinde et al.64
T3SS	MxiM	MxiJ	MxiD	Shigella flexneri	Schuch and Maurelli65 Lario et al.56 Okon et al.66
	ExsB		PscC	Pseudomonas aeruginosa	Izoré et al.57 Perdu et al.67
	YscW		YscC	Yersinia enterocolitica	Burghout et al.68 Ross and Plano132
	InvH		InvG	Salmonella enterica	Daefler and Russell69 Craig and Koronakis70
	YsaP		YsaC	Yersinia enterocolitica	Rau and Darwin71
T4aPS	PilW	PilP	PilQ	Neisseria meningitidis	Trindade et al.59 Carbonnelle et al.72 Golovanov et al.58
	PilF		PilQ	Pseudomonas aeruginosa	Koo et al.60
	Tgl		PilQ	Myxococcus xanthus	Nudleman et al.73
T4bPS		BfpG	BfpB	Escherichia coli	Lieberman et al.74
		TcpQ	TcpC	Vibrio cholerae	Chang et al.75
		FimV	PilQ	Pseudomonas aeruginosa	Wehbi et al.76
		CpaE	CpaC	Caulobacter crescentus	Viollier et al.77
	TadD		RcpA	Aggregatibacter actinomycetemcomitans	Clock et al.78