The human PIM-1 gene product is a protein serine kinase.

The human PIM-1 gene, a homologue of murine retroviral insertion site mpim-1, is overexpressed in a subset of hematolymphoid malignancies. Deduced amino acid sequence of PIM-1 complementary DNA predicts it to be a protein kinase. In vitro transcription coupled translation of the putative 313-amino acid open reading frame yields a Mr 34,000 protein; an immune complex kinase assay of the wild-type PIM-1 and not a site-directed mutant, in which the invariant Lys67 has been changed to Arg, demonstrates autophosphorylating activity on serine residues. Thus, PIM-1 is a protein serine kinase with a possible role in neoplastic transformation.