. 2019 Feb 15;7(1):10.1128/microbiolspec.psib-0002-2018. doi: 10.1128/microbiolspec.psib-0002-2018

TABLE 1.

T9SS components^a

P. gingivalis protein name or locus tag^b	F. johnsoniae protein name or locus tag	Localization	Predicted role in secretion/motility	Essential for F. johnsoniae gliding?	Interaction partner	Notes	Reference(s)
Secretion complex
PorL	GldL	CM	Energizes secretion/motility	Essential	PorM	Forms complex with PorK, PorM, and PorN	18, 19, 23, 61
PorM	GldM	CM	Energizes secretion/motility	Essential	PorK, PorL, PorN, PorP	Forms complex with PorK, PorL, and PorN	18, 19, 23, 61, 62
PorK	GldK	OM lipoprotein	Component of periplasmic channel	Essential	PorM, PorN, PorP, PG0189	Forms complex with PorL, PorM, and PorN	18, 19, 23, 60, 61
PorN	GldN and GldO	P	Component of periplasmic channel	Essential	PorK, PorM, PG0189	Forms complex with PorK, PorL, and PorM	18, 19, 22, 23, 60, 61
Sov	SprA	OM	OM pore	Nearly essential	PorV, plug		19, 30, 31, 58, 64
PorT	SprT	OM	Unknown	Nearly essential	ND		23, 29, 71
PorP	SprF and 9 other PorP-like proteins^c	OM	Unknown	ND	PorK, PorM		23, 46, 59, 61
PorW	SprE	OM lipoprotein	Unknown	Nearly essential	ND		23, 72
PG1058 (PGN_1296)	Fjoh_1647,^d Fjoh_2275, Fjoh_3950, Fjoh_3973, Fjoh_4540	OM lipoprotein	Anchors T9SS to peptidoglycan	ND	ND	OmpA C-terminal peptidoglycan-binding domain	57
PG0189 (PGN_0297)	Fjoh_1692	OM	Unknown	ND	PorK, PorN		60
PG2092 (PGN_0144)	Fjoh_1759, plug	P/OM	Forms plug on periplasmic side of SprA pore. Prevents nonspecific leakage of periplasmic contents.	ND	SprA		64
Attachment complex
PorV^e	PorV	OM	Shuttles secreted proteins from secretion complex to attachment complex	Not needed for gliding	PorU, SprA	Forms complex with PorU, PorQ, and PorZ	32, 34, 56, 64, 73, 74
PorU	PorU	Cell surface	CTD cleavage; attachment of substrates to A-LPS	Not needed for gliding	PorV	Forms complex with PorV, PorQ, and PorZ	39, 56, 73
PorQ	Fjoh_2755	OM	Unknown	Not needed for gliding		Forms complex with PorU, PorV, and PorZ	23, 56
PorZ	Fjoh_0707	Cell surface	Assembly of PorU on cell surface; secretion and/or modification of secreted proteins	ND		Forms complex with PorU, PorV, and PorQ	45, 56
Other
PG0534 (PGN_1437)	Fjoh_0118	OM	Secretion and/or modification of secreted proteins	ND			65
Omp17; PG0192 (PGN_0300)	Fjoh_0599,^f Fjoh_1000, Fjoh_1688, Fjoh_1689	OM	PorU maturation or stabilization; post-secretion processing	ND		OmpH-like	66

^{^a}

Abbreviations: CM, cytoplasmic membrane; OM, outer membrane; P, periplasm; ND, not determined.

^{^b}

Locus tags for P. gingivalis strains W83 (PG) and ATCC33277 (PGN_) are listed, with the PGN_ locus tags in parentheses.

^{^c}

PorP-like proteins recognized by assignment to Tigrfam “type IX secretion system membrane protein PorP/SprF family” TIGR03519.

^{^d}

PG1058-like proteins recognized by the presence of domains corresponding to pfam00691 (OmpA_C terminal domain), pfam07676 (WD40-like Beta propeller repeat), and pfam13620 (carboxypeptidase regulatory-like domain).

^{^e}

PorV may be a component of the secretion complex and the attachment complex.

^{^f}

Proteins related to PG0192 (PGN_0300) recognized by the presence of domains corresponding to pfam03938 (OmpH-like).