Zipa

ZipA is a bacterial cell division protein found predominantly in Gram-negative bacteria such as Escherichia coli. It is a core component of the divisome, the protein complex that drives cytokinesis, and functions as a membrane tether for the FtsZ cytoskeletal ring, helping to anchor the Z-ring to the inner membrane.

ZipA is an inner membrane protein with an N-terminal transmembrane helix that anchors it to the cytoplasmic membrane and a large cytoplasmic domain that binds FtsZ. The interaction primarily involves the C-terminal region of FtsZ and serves to stabilize and localize the Z-ring during division. ZipA can also interact with other divisome components, including FtsA, contributing to the coordination of constriction and division dynamics.

Genetic and evolutionary context: The zipA gene lies within the dcw (division and cell wall) gene cluster, near ftsZ, and is conserved among many Gram-negative bacteria. While ZipA plays a significant role in divisome assembly, cells can sometimes tolerate reduced or absent ZipA under certain conditions, indicating functional redundancy with other membrane tethers and context-dependent essentiality.

Additional notes: In research, ZipA has been used to study Z-ring formation, membrane tethering, and divisome architecture. The exact oligomeric state of ZipA can vary by species and condition, with evidence for dimeric or higher-order assemblies contributing to divisome organization in some contexts.