PilZ is a c-di-GMP binding domain [3] found in widespread cytoplasmic receptors, which is involved in regulation of motility, biofilm formation and virulence of many bacterial pathogens. This domain binds c-di-GMP through RXXXR and [D/N]hSXXG motifs, however, some PilZ domains lack these motifs and do not bind c-di-GMP [6]. Proteins which contain PilZ are known to interact with the flagellar switch-complex proteins FliG and FliM. This interaction results in a reduction of torque generation and induces CCW motor bias [5]. This is the canonical PilZ domain whose structure consists of six beta-strands that form a beta barrel, followed by a long C-terminal alpha-helix [6].

1: Identification of a novel gene, pilZ, essential for type 4 fimbrial biogenesis in Pseudomonas aeruginosa. Alm RA, Bodero AJ, Free PD, Mattick JS; J Bacteriol 1996;178:46-53. PMID:8550441

2: PilZ domain is part of the bacterial c-di-GMP binding protein. Amikam D, Galperin MY; Bioinformatics. 2006;22:3-6. PMID:16249258

3: The PilZ domain is a receptor for the second messenger c-di-GMP: the PilZ domain protein YcgR controls motility in enterobacteria. Ryjenkov DA, Simm R, Romling U, Gomelsky M; J Biol Chem. 2006;281:30310-30314. PMID:16920715

4: The structural basis of cyclic diguanylate signal transduction by PilZ domains. Benach J, Swaminathan SS, Tamayo R, Handelman SK, Folta-Stogniew E, Ramos JE, Forouhar F, Neely H, Seetharaman J, Camilli A, Hunt JF; EMBO J. 2007;26:5153-5166. PMID:18034161

5: The c-di-GMP binding protein YcgR controls flagellar motor direction and speed to affect chemotaxis by a "backstop brake" mechanism. Paul K, Nieto V, Carlquist WC, Blair DF, Harshey RM; Mol Cell. 2010;38:128-139. PMID:20346719

6: Structural Conservation and Diversity of PilZ-Related Domains. Galperin MY, Chou SH; J Bacteriol. 2020; [Epub ahead of print] PMID:31740493