Intracellular osteopontin (iOPN) and immunity.
Osteopontin (OPN) is a protein involved in various pathophysiological events. OPN has been studied as a secreted protein, but recent reports showed that OPN can be found in the cytoplasm and the nucleus. Therefore, some OPN molecules are not secreted and stay in cells. Such intracellular OPN (iOPN) has biological functions distinct from secreted OPN (sOPN). iOPN is involved in cytoskeletal rearrangement and in signal transduction pathways downstream of innate immune receptors, such as Toll-like receptors (TLRs), as an adaptor or scaffolding protein. Although sOPN and iOPN are generated from the same Opn mRNA species, biological outcomes mediated by two isoforms can be different. It would be necessary to delineate which isoform of OPN is responsible for pathophysiological events.
Department of Immunology, School of Medicine, Duke University, 338 Jones Building, DUMC 3010, Durham, NC 27710, USA.
Makoto
M
Inoue
Mari L
ML
Shinohara
D000818:Animals; D002448:Cell Adhesion; D006801:Humans; D007113:Immunity, Innate; D042541:Intracellular Space / Q000276:immunology / Q000378:metabolism; D053495:Osteopontin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000378:metabolism
D051193:Toll-Like Receptors; D053495:Osteopontin