Location, location, location: Membrane targeting directed by PX domains

Phosphoinositide (PI)-binding domains play critical roles in the intracellu lar localization of a variety of cell-signaling proteins. The 120-amino aci d Phox homology (PX) domain targets proteins to organelle membranes through interactions between two conserved basic motifs within the PX domain and s pecific PIS. The combination of protein-lipid and protein-protein interacti ons ensures the proper Localization and regulation of PX domain-containing proteins. Upon proper Localization, PX domain-containing proteins can then bind to additional proteins and execute their functions in a diverse set of biological pathways, including intracellular protein transport, cell growt h and survival, cytoskeletal organization, and neutrophil defense.