Type IV filament

{{Short description|Family of cell projections including T2SS and T4P}}

The type IV filament superfamily (TFF) is a group of fibrous protein structures that includes a set of cell projections with evolutionarily related membrane proteins.{{cite journal | vauthors = Berry JL, Pelicic V | title = Exceptionally widespread nanomachines composed of type IV pilins: the prokaryotic Swiss Army knives | journal = FEMS Microbiology Reviews | volume = 39 | issue = 1 | pages = 134–54 | date = January 2015 | pmid = 25793961 | pmc = 4471445 | doi = 10.1093/femsre/fuu001 }} The TFF family seems to have originated in the last universal common ancestor, from where it diversified into archaella, type IV pili, type II secretion systems, and the Tad pili.{{cite journal | vauthors = Denise R, Abby SS, Rocha EP | title = Diversification of the type IV filament superfamily into machines for adhesion, protein secretion, DNA uptake, and motility | journal = PLOS Biology | volume = 17 | issue = 7 | pages = e3000390 | date = July 2019 | pmid = 31323028 | pmc = 6668835 | doi = 10.1371/journal.pbio.3000390 | veditors = Beeby M | doi-access = free }}

Complexes in the TFF superfamily are unified by the presence of the eponymous type IV pilin, an AAA+ ATPase, an integral (cytoplasmic) membrane (IM) platform, and (with the exception of MSH) a prepilin peptidase.