Table 1.

Cytoskeletal, cytomotive, independent and collaborative filaments: systematic nomenclature and examples

AN	Cytoskeletal filament	IF, crescentin
ANXPN	Cytomotive filament driven by nucleotide NXP	Single FtsZ protofilament
2P(ANXP)N	2 parallel protofilaments of cytomotive filament	Actin, ParM
4P(ANXP)N	4 parallel protofilaments of cytomotive filaments	TubZ
5P(ANXP:BNXP)N	5 parallel protofilaments of cytomotive copolymer	BtubAB (mini-microtubule)
13P(ANXP:BNXP)N	13 parallel protofilaments of cytomotive copolymer	Microtubule
AN:DNA	Collaborative filament on DNA	Dan filaments on DNA
ANXPN:DNA	Cytomotive, collaborative filament on DNA	ParA, RecA on DNA
AN:M	Collaborative filament on membrane	DivIVA on membrane
ANXPN:M	Cytomotive, collaborative filament on membrane	FtsA on membrane
2A(ANXP)N:M	2 antipar. protofil. of cytom. filament on membrane	MreB on membrane
(ANXPN:BNXPN):M	Two cytomo. filaments copolymerised on membrane	FtsZ:FtsA on membrane
(A:BNXP)N:M	Cytomotive, alternating copolymer on membrane	MinCD, septin on membrane
CNXPN:(A:BNXP)N:M	Above bound to another cytomotive filament	MinCD: FtsZ on membrane

Superscript N denotes polymerisation of the monomer A and NXP stands for nucleotide (ATP/ADP/GTP/GDP etc) that may be hydrolysed by a cytomotive filament. Colon represents binding of subunits to each other or to a matrix or scaffold, and brackets are used to group these interactions until there is no ambiguity. The number of protofilaments is indicated at the very beginning with a subscript P or A implying parallel or antiparallel arrangement.