Domain

PilZ domain (IPR009875)

Short name: PilZ_domain

Domain relationships

Description

The ubiquitous bacterial second messenger cyclic-di-GMP (c-di-GMP) is associated with the regulation of biofilm formation, the control of exopolysaccharide synthesis, flagellar- and pili-based motility, gene expression, interactions of bacteria with eukaryotic hosts and multicellular behaviour in diverse bacteria.

With the exception of bacterial cellulose synthases, the identities of c-di-GMP receptors and end targets of the proteins having one or more PilZ domains are mostly uncharacterised. However it was suggested that the PilZ domains present in the BcsA subunits of bacterial cellulose synthases function in c-di-GMP binding [PMID: 16249258]. More recently YcgR (see IPR023787) was found to bind c-di-GMP tightly and specifically; also isolated PilZ domains from YcgR and BcsA bound c-di-GMP indicating that the PilZ domain was sufficient for binding of c-di-GMP and significantly that site-directed mutagenesis performed on YcgR implicated the most conserved residues in the PilZ domain directly in c-di-GMP binding [PMID: 16920715]. It was suggested that c-di-GMP binding to PilZ brings about conformational changes in the protein that stabilise the bound ligand and probability initiates the downstream signal transduction cascade. In the case of YcgR, c-di-GMP binding regulates flagellum-based motility in a c-di-GMP-dependent manner (see IPR023787) [PMID: 16920715]. The association of the PilZ domain with a variety of other domains, including likely components of bacterial multidrug secretion system, could provide clues to multiple functions of the c-di-GMP in bacterial pathogenesis and cell development.

Binding and mutagenesis studies of several PilZ domain proteins have confirmed this observation and demonstrated that c-di-GMP binding depends on residues in RxxxR and D/NxSxxG sequence motifs. The crystal structure, at 1.7 A, of a PilZ domain::c-di-GMP complex from Vibrio cholerae shows c-di-GMP contacting seven of nine strongly conserved residues. Binding of c-di-GMP causes a conformational switch whereby the C- and N-terminal domains are brought into close opposition forming a new allosteric interaction surface that spans these domains and the c-di-GMP at their interface [PMID: 18034161].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0035438 cyclic-di-GMP binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
Pfam