The second LIM domain of Arrowhead (AWH): Arrowhead belongs to the LHX protein family, which features two tandem N-terminal LIM domains and a C-terminal DNA binding homeodomain. Members of LHX family are found in the nucleus and act as transcription factors or cofactors. LHX proteins are critical for the development of specialized cells in multiple tissue types, including the nervous system, skeletal muscle, the heart, the kidneys, and endocrine organs such as the pituitary gland and the pancreas. During embryogenesis of Drosophila, Arrowhead is expressed in each abdominal segment and in the labial segment. Late in embryonic development, expression of arrowhead is refined to the abdominal histoblasts and salivary gland imaginal ring cells themselves. The Arrowhead gene required for establishment of a subset of imaginal tissues: the abdominal histoblasts and the salivary gland imaginal rings. 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.
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.",