Murine DEP-1, a receptor protein tyrosine phosphatase, is expressed in macrophages and is regulated by CSF-1 and LPS

The spectrum of protein tyrosine phosphatases (PTPs) expressed in bone marrow‐derived murine macrophages (BMMs) was examined using reverse transcriptase‐polymerase chain reaction. Ten different PTP cDNAs were isolated and in this study we focus on mDEP‐1, a type III receptor PTP. Three mDEP‐1 transcripts were expressed in primary macrophages and macrophage cell lines and were induced during macrophage differentiation of M1 myeloid leukemia cells. A variant mRNA was identified that encodes an alternate carboxyl‐terminus and 3 UTR. The expression of mDEP‐1 was down‐regulated by CSF‐1 (macrophage colony‐stimulating factor) and up‐regulated by bacterial lipopolysaccharide, an important physiological regulator of macrophage function that opposes CSF‐1 action. Whole mount in situ hybridization, and immunolocalization of the protein, confirmed that mDEP‐1 is expressed by a subset of embryonic macrophages in the liver and mesenchyme. mDEP‐1 was also detected in the eye and peripheral nervous system of the developing embryo. Attempts to express mDEP‐1 constitutively in the macrophage cell line RAW264 were unsuccessful, with results suggesting that the gene product inhibits cell proliferation. J. Leukoc. Biol. 64: 692–701; 1998.