Molecular characterization of peptidylarginine deiminase in HL-60 cells induced by retinoic acid and 1 alpha,25-dihydroxyvitamin D-3

Three types of peptidylarginine deiminase (PAD), which converts a protein a rginine residue to a citrulline residue, are widely distributed in animal t issues. Little is known about PAD of hemopoietic cells. We found that PAD a ctivity in human myeloid leukemia HL-60 cells was induced with the granuloc yte-inducing agents retinoic acid and dimethyl sulfoxide and with the monoc yte-inducing agent 1 alpha,25-dihydroxyvitamin D-3. We cloned and character ized a PAD cDNA from retinoic acid-induced cells. The cDNA was 2,238 base p airs long and encoded a 663-amino acid polypeptide. The HL-60 PAD had 50-55 % amino acid sequence identities with the three known enzymes and 73% ident ity with the recently cloned keratinocyte PAD. The recombinant enzyme diffe rs in kinetic properties from the known enzymes. Immunoblotting and Norther n blotting with an antiserum against the enzyme and the cDNA, respectively, showed that a protein of approximately 67 kDa increased concomitantly with increase of mRNA of approximately 2.6 kilobases during granulocyte differe ntiation. During monocyte differentiation the same mRNA and protein increas ed as in granulocyte differentiation. Neither the enzyme activity nor the p rotein was found in macrophage-induced cells. These results suggested that expression of the PAD gene is tightly linked to myeloid differentiation.