Oncostatin M (OSM) is a member of a cytokine subfamily that includes IL-6, IL-11, LIF, CNTF, and cardiotrophin-1. These cytokines have overlapping biological functions and shared receptor components. Mouse OSM was cloned and identified as an immediate early gene induced in various myeloid and lymphoid cell lines by a subset of cytokines including IL-2, IL-3, GM-CSF and EPO. The mouse OSM cDNA encodes a 263 amino acid residue precursor protein that shows 48% identity with human OSM. Similar to human OSM, the C-terminal region of mouse OSM contains a highly charged region. Deletion of this C-terminal region appears to be essential for the formation of biologically active mOSM.
The biological activity of human OSM has been shown to be mediated either by the LIF/OSM receptor complex composed of gp130 and LIF R alpha or by a human OSM specific receptor composed of gp130 and OSM R alpha. It remains to be determined if the biological activities of mouse OSM can also be mediated by both receptor complexes in mouse cells.
