Apte et al. (1994) isolated overlapping cDNAs encoding a novel member of the group, TIMP3. The cDNAs contained a 591-bp open reading frame encoding 9 amino acid residues of the signal peptide and 188 residues of the mature TIMP3 polypeptide. Both the nucleotide sequence and the deduced translation product of the TIMP3 cDNA had a high degree of similarity to the TIMP1 and TIMP2 gene products, including 12 conserved cysteinyl residues at the same relative positions. The TIMP3 gene is expressed in many tissues, with highest expression in the placenta. Wilde et al. (1994) cloned and sequenced TIMP3 from phorbol ester-differentiated cells stimulated with bacterial lipopolysaccharide. The open reading frame encoded a 211-amino acid precursor, including a 23-residue secretion signal. The mature polypeptide had a calculated molecular weight of 21.6 kD.