The fourth LIM domain of Leupaxin: Leupaxin is a cytoskeleton adaptor protein, which is preferentially expressed in hematopoietic cells. Leupaxin belongs to the paxillin focal adhesion protein family. Same as other members of the family, it has four leucine-rich LD-motifs in the N-terminus and four LIM domains in the C-terminus. It may function in cell type-specific signaling by associating with interaction partners PYK2, FAK, PEP and p95PKL. When expressed in human leukocytic cells, leupaxin significantly suppressed integrin-mediated cell adhesion to fibronectin and the tyrosine phosphorylation of paxillin. These findings indicate that leupaxin may negatively regulate the functions of paxillin during integrin signaling. LIM domains are 50-60 amino acids in size and share two characteristic zinc finger motifs. The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. LIM domains function as adaptors or scaffolds to support the assembly of multimeric protein complexes.
Comment: The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. The Zn binding residues of LIM domain are highly conserved.
Jiyao W et al.(2023). "The conserved domain database in 2023.",