Pxn

Pxn is most commonly used to refer to the PXN gene in humans, which encodes paxillin, a cytoskeletal adaptor protein that localizes to focal adhesions and participates in signaling pathways that control cell adhesion, migration, and shape. The term pxn can also appear as a shorthand in non-biological contexts, including as a brand name in consumer electronics.

Paxillin is a scaffold protein that coordinates signaling at focal adhesions, the contact points between cells and the extracellular matrix. It contains multiple LD motifs at the N-terminus that mediate interactions with other focal adhesion components, and LIM domains at the C-terminus that bind additional partners. Through these domains, paxillin links integrins to intracellular signaling networks and cytoskeletal rearrangements, influencing processes such as cell spreading, migration, and mechanotransduction. Paxillin interacts with kinases and structural proteins, including focal adhesion kinase (FAK), Src family kinases, talin, vinculin, and p130Cas, enabling coordinated regulation of adhesion dynamics and actin organization.

Regulation occurs via phosphorylation at several residues, altering binding interactions and localization. Tyrosine phosphorylation by Src and FAK, as well as serine/threonine phosphorylation, modulates paxillin’s activity and its recruitment to adhesions. Paxillin’s localization at focal adhesions is dynamic, changing during adhesion formation and disassembly and in response to mechanical cues and growth factor signaling.

Clinical and research relevance: Altered PXN expression or function has been linked to cancer progression and metastasis in various tumor types, and paxillin is studied as a potential biomarker and therapeutic target in some contexts. It also has roles in development and wound healing in model systems.