The first LIM domain of Testin_like family: This family includes testin, prickle, dyxin and LIMPETin. Structurally, testin and prickle proteins contain three LIM domains at C-terminal; LIMPETin has six LIM domains; and dyxin presents only two LIM domains. However, all members of the family contain a PET protein-protein interaction domain. Testin is a cytoskeleton associated focal adhesion protein that localizes along actin stress fibers, at cell-cell-contact areas, and at focal adhesion plaques. Testin interacts with a variety of cytoskeletal proteins, including zyxin, mena, VASP, talin, and actin and it is involved in cell motility and adhesion events. Prickles have been implicated in roles of regulating tissue polarity or planar cell polarity (PCP). Dyxin involves in lung and heart development by interaction with GATA6 and blocking GATA6 activated target genes. LIMPETin might be the recombinant product of genes coding testin and four and half LIM proteins and its function is not well understood. As in other LIM domains, this domain family is 50-60 amino acids in size and shares 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.",