Leupaxin (LPXN)

Leupaxin is preferentially expressed in hematopoietic cells and is most homologous to the focal adhesion protein, paxillin. It may function in cell type-specific signaling by associating with PYK2. As a substrate for a tyrosine kinase in lymphoid cells, this protein may also function in, and be regulated by tyrosine kinase activity. LPXN shares 37% overall amino acid sequence identity with the focal adhesion protein paxillin (PXN). The C terminus of LPXN contains 4 LIM domains that share 67 to 76% identity with the LIM domains of PXN. Its N terminus contains 3 LD motifs, which were first identified in PXN as 13-amino acid motifs with an invariable leucine and aspartate pair. LD motifs in PXN have been implicated in binding to cytoplasmic PTK2 and vinculin, resulting in localization of PTK2 to focal adhesions.