The collagen receptor uPARAP/Endo180.
The uPAR-associated protein (uPARAP/Endo180), a type-1 membrane protein belonging to the mannose receptor family, is an endocytic receptor for collagen. Through this endocytic function, the protein takes part in a previously unrecognized mechanism of collagen turnover. uPARAP/Endo180 can bind and internalize both intact and partially degraded collagens. In some turnover pathways, the function of the receptor probably involves an interplay with certain matrix-degrading proteases whereas, in other physiological processes, redundant mechanisms involving both endocytic and pericellular collagenolysis seem to operate in parallel. On certain cell types, uPARAP/Endo180 occurs in a complex with the urokinase plasminogen activator receptor (uPAR) where it seems to fulfill other functions in addition to collagenolysis. uPARAP/Endo180 is expressed on various mesenchymal cells, including subpopulations of fibroblasts, osteoblasts and chondrocytes, generally in conjunction with matrix turnover and collagenolysis. A striking expression is found in developing bone where the collagenolytic function of uPARAP/Endo180 is one of the rate-limiting steps in growth. In murine breast tumors, the endocytic function of the receptor in collagen breakdown seems to be involved in invasive tumor growth.
Engelholm
Lars H
LH
The Finsen Laboratory, Rigshospitalet section 3735, Copenhagen Biocenter, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark. lars@engelholm.dk
Ingvarsen
Signe
S
Jürgensen
Henrik J
HJ
Hillig
Thore
T
Madsen
Daniel H
DH
Nielsen
Boye S
BS
Behrendt
Niels
N
D006801:Humans; D037241:Mannose-Binding Lectins / Q000737:chemistry / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D011975:Receptors, Mitogen / Q000737:chemistry / Q000378:metabolism*
C408294:Endo180; C404106:MRC2 protein, human; D037241:Mannose-Binding Lectins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011975:Receptors, Mitogen