Table 3.2.

Proteins of the B. subtilis divisome and its regulators

Protein	MW (kDa)	Locationa	Comments	Key references
FtsZ	40	C	Tubulin-like protein. Assembles into protofilaments and higher order structures to generate the “Z ring” at the division site. Recruits other divisome proteins to the ring.	Beall et al. (1988), Beall and Lutkenhaus (1991), and Wang and Lutkenhaus (1993)
FtsA	48	C	Actin / HSP70 superfamily ATPase. Dimerises and can form higher order structures. C-terminal amphipathic helix promotes membrane association. Direct interaction with FtsZ, which contributes to membrane association of the Z ring.	Beall and Lutkenhaus (1991), Feucht et al. (2001), Jensen et al. (2005) and Ishikawa et al. (2006)
SepF	17	C	Forms regular 50 nm diameter rings in vitro and interacts directly with FtsZ in vitro, promoting FtsZ bundling. Membrane targeting domain contributes to membrane association of the Z ring.	Hamoen et al. (2006) and Gündoğdu et al. (2011)
ZapA	9.0	C	Widely conserved protein that promotes Z ring formation by direct interaction with FtsZ.	Gueiros-Filho and Losick (2002)
EzrA	65	C	N-terminal transmembrane anchor. Cytosolic domain has a spectrin-like fold. Interacts with FtsZ, contributing to membrane association of the Z ring. Additional role in cell elongation via interactions with PBP 2B and GpsB.	Levin et al. (1999), Haeusser et al. (2004), Claessen et al. (2008), and Cleverley et al. (2014)
GpsB	11	C	DivIVA-related protein involved in both cell elongation and cell division. Interacts with the major PG synthase, PBP 1, and thought to be involved in shuttling of this protein between elongation and division complexes. Synthetic lethal in combination with ftsA mutation. Synthetic “sick” in combination with ezrA. EzrA-SepF interaction probably important for shuttling.	Claessen et al. (2008) and Tavares et al. (2008)
FtsL	13	E	Bitopic membrane protein with short extracytoplasmic coiled-coil-like domain. Target of several cell division regulatory mechanisms. Unstable protein subject to degradation by a regulated intramembrane proteolysis (RIP) process involving YluC protease. Stability also regulated by interactions with DivIC and DivIB.	Daniel et al. (1998), Daniel and Errington (2000), Sievers and Errington (2000a, b), Kawai and Ogasawara (2006), Bramkamp et al. (2006) and Daniel et al. (2006)
DivIB	30	E	Bitopic membrane protein with large extracellular domain. Structural data from other organisms suggests two domains, one of which resembles the POTRA domain often involved in protein protein interactions. Complex pattern of interactions with FtsL and DivIC. Homologue called FtsQ in E. coli.	Beall and Lutkenhaus (1989), Harry and Wake (1989, 1997), Katis and Wake (1999), Katis et al. (2000), Daniel and Errington (2000) and Daniel et al. (2006)
DivIC	15	E	Bitopic membrane protein with short extracytoplasmic coiled-coil-like domain. Interacts with FtsL and DivIB. Likely homologue confusingly called FtsB in E. coli.	Katis et al. (1997), Katis and Wake (1999), Katis et al. (2000), Sievers and Errington (2000b), Robson et al. (2002) and Daniel and Errington (2000)
FtsW	44	I	Integral membrane protein closely related to RodA involved in cell elongation.	Lu et al. (2007)
Pbp2B	79	E	Penicillin binding protein. Monofunctional (class B) transpeptidase specifically required for cell division.	Yanouri et al. (1993), Daniel et al. (1996) and Daniel and Errington (2000)
DivIVA	19	C	Coiled coil protein with weak similarity to eukaryotic tropomyosins. Targeted to division sites and cell poles at least in part by sensing membrane curvature. Membrane interaction through conserved N-terminal domain containing essential tryptophan residue. Involved in a range of cell pole associated functions in Gram positive bacteria.	Cha and Stewart (1997), Edwards and Errington (1997), Hamoen and Errington (2003) and Lenarcic et al. (2009), Ramamurthi and Losick (2009) and Van Baarle et al. (2013)
MinC	25	C	Widely conserved division inhibitor acting on FtsZ and possibly other steps in division.	Reeve et al. (1973), Levin et al. (1992), Marston and Errington (1999) and Gregory et al. (2008)
MinD	29	C	Widely conserved indirect division inhibitor that works by spatial regulation of MinC protein. Poorly characterised additional role in chromosome segregation during sporulation.	Reeve et al. (1973), Levin et al. (1992), Marston et al. (1998) and Marston and Errington (1999), Kloosterman et al. (2016)
MinJ	44	I / C	PDZ-domain protein targeted to cell poles by interaction with DivIVA (at least). Required for correct spatial localization of the MinCD complex and thus the regulation of cell division.	Patrick and Kearns (2008), Bramkamp et al. (2008) and Van Baarle and Bramkamp (2010)
Noc	33	C	Site-specific DNA binding protein. Inhibitor of division. Major factor effecting nucleoid occlusion.	Wu and Errington (2004), Wu et al. (2009) and Adams et al. (2015)
WhiA	36	C	Enigmatic nucleoid associated factor. whiA mutation causes severe filamentation when combined with zapA, ezrA or various regulatory proteins of cell division.	Surdova et al. (2013)
SpoIIE	92	C/I	Bifunctional sporulation-specific protein. C-terminal kinase domain regulates prespore-specific gene expression. C-terminal domain required for efficient switch in cell division position from mid cell to sub-polar position, probably via a direct interaction with FtsZ.	Arigoni et al. (1995), Feucht et al. (1996), Wu et al. (1998), Lucet et al. (2000), Carniol et al. (2005) and Bradshaw and Losick (2015)
MciZ	4.0	C	Mother cell-specific inhibitor of FtsZ assembly. Caps FtsZ protofilaments at the “minus” end.	Handler et al. (2008) and Bisson-Filho et al. (2015)
RefZ	24	C	Site-specific DNA-binding protein that contributes to precise relative positioning of chromosome and asymmetric division site during sporulation.	Wagner-Herman et al. (2012) and Miller et al. (2015)

^a C cytosolic, I integral membrane, E extracytoplasmic