Matrilins mediate weak cell attachment without promoting focal adhesion formation.
The matrilins form a family of non-collagenous adaptor proteins in the extracellular matrix. The extracellular ligand interactions of matrilins have been studied in some detail, while the potential interplay between matrilins and cells has been largely neglected. Except for matrilin-4, all matrilins mediate cell attachment, but only for matrilin-1 and -3 the binding is clearly dose dependent and seen already at moderate coating concentrations. Even so, much higher concentrations of matrilin-1 or -3 than of fibronectin are required for cell attachment to reach plateau values. Integrins contribute to the matrilin-mediated cell attachment, but the binding does not lead to formation of focal contacts and reorganisation of the actin cytoskeleton. Cells deficient in beta1 integrins are able to adhere, although weaker, and matrilins do not bind the soluble integrin alpha1beta1 and alpha2beta1 ectodomains. Cell surface proteoglycans may promote the attachment, as cells deficient in glycosaminoglycan biosynthesis adhere less well to matrilin-3. Even so, exogenous glycosaminoglycans are not able to compete for the attachment of HaCaT cells to matrilins.
Mann
Henning H
HH
Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
Sengle
Gerhard
G
Gebauer
Jan M
JM
Eble
Johannes A
JA
Paulsson
Mats
M
Wagener
Raimund
R
D000818:Animals; D064236:Cartilage Oligomeric Matrix Protein; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology*; D002460:Cell Line; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D039222:Integrin alpha1beta1 / Q000378:metabolism; D038982:Integrin alpha2beta1 / Q000378:metabolism; D064235:Matrilin Proteins
D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D006025:Glycosaminoglycans; D039222:Integrin alpha1beta1; D038982:Integrin alpha2beta1; C577539:MATN1 protein, human; D064235:Matrilin Proteins; C577553:TSP5 protein, human