WARP is a novel multimeric component of the chondrocyte pericellular matrix that interacts with perlecan.
WARP is a novel member of the von Willebrand factor A domain superfamily of extracellular matrix proteins that is expressed by chondrocytes. WARP is restricted to the presumptive articular cartilage zone prior to joint cavitation and to the articular cartilage and fibrocartilaginous elements in the joint, spine, and sternum during mouse embryonic development. In mature articular cartilage, WARP is highly specific for the chondrocyte pericellular microenvironment and co-localizes with perlecan, a prominent component of the chondrocyte pericellular region. WARP is present in the guanidine-soluble fraction of cartilage matrix extracts as a disulfide-bonded multimer, indicating that WARP is a strongly interacting component of the cartilage matrix. To investigate how WARP is integrated with the pericellular environment, we studied WARP binding to mouse perlecan using solid phase and surface plasmon resonance analysis. WARP interacts with domain III-2 of the perlecan core protein and the heparan sulfate chains of the perlecan domain I with K(D) values in the low nanomolar range. We conclude that WARP forms macromolecular structures that interact with perlecan to contribute to the assembly and/or maintenance of "permanent" cartilage structures during development and in mature cartilages.
Allen
Justin M
JM
Cell and Matrix Biology Research Unit, Murdoch Childrens Research Institute and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia.
Bateman
John F
JF
Hansen
Uwe
U
Wilson
Richard
R
Bruckner
Peter
P
Owens
Rick T
RT
Sasaki
Takako
T
Timpl
Rupert
R
Fitzgerald
Jamie
J
D020816:Amino Acid Motifs; D000818:Animals; D002356:Cartilage / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism; D002460:Cell Line; D019902:Chondrocytes / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000502:physiology*; D019812:Heparan Sulfate Proteoglycans / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D007700:Kinetics; D051379:Mice; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D020349:Surface Plasmon Resonance; D013997:Time Factors; D014018:Tissue Distribution; D014841:von Willebrand Factor / Q000737:chemistry
D018076:DNA, Complementary; D004220:Disulfides; D016326:Extracellular Matrix Proteins; D019812:Heparan Sulfate Proteoglycans; D012333:RNA, Messenger; D011994:Recombinant Proteins; C460760:VWA1 protein, human; D014841:von Willebrand Factor; C071927:perlecan