Tartrate-resistant acid phosphatase (TRAP) and the osteoclast/immune cell dichotomy.
Tartrate-resistant acid phosphatase (TRAP), once considered to be just a histochemical marker of osteoclasts is now recognised to be a molecule of widespread occurrence with functions in both the skeleton and the immune system. TRAP is expressed by osteoclasts, macrophages, dendritic cells and a number of other cell types. It has a critical role in many biological processes including skeletal development, collagen synthesis and degradation, the mineralisation of bone, cytokine production by macrophages and dendritic cells, macrophage recruitment, dendritic cell maturation and a role in the development of Th1 responses. TRAP is able to degrade skeletal phosphoproteins including osteopontin (OPN), identical to the T-cell cytokine, Eta-1. In this review, we discuss the role of TRAP in bone and immune cells and suggest that TRAP may be implicated in autoimmune disorders regulated by Th1 inflammatory responses as well as certain cancers.
Hayman
Alison R
AR
School of Clinical Veterinary Science, University of Bristol, Bristol, UK.
D000135:Acid Phosphatase / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D001862:Bone Resorption / Q000201:enzymology / Q000276:immunology; D001842:Bone and Bones / Q000201:enzymology* / Q000276:immunology*; D006801:Humans; D007527:Isoenzymes / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010010:Osteoclasts / Q000201:enzymology* / Q000276:immunology*; D053495:Osteopontin / Q000378:metabolism; D020033:Protein Isoforms; D000071681:Tartrate-Resistant Acid Phosphatase; D018417:Th1 Cells / Q000201:enzymology / Q000276:immunology
D007527:Isoenzymes; D020033:Protein Isoforms; D053495:Osteopontin; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase