Extracellular matrix adhesion-promoting activities of a dermatan sulfate proteoglycan-associated protein (22K) from bovine fetal skin.
A 22 x 10(3) Mr protein (abbreviated 22K) that copurifies with dermatan sulfate proteoglycans (DS-PGs) following the biochemical fractionation of bovine fetal skin has been evaluated for adhesion-promoting activity in vitro using Balb/c 3T3 cells, as well as bovine and human dermal fibroblasts. Substrata coated with 22K protein promote attachment of a subset of 3T3 and dermal fibroblasts that respond to plasma fibronectin (pFN) substrata. Cells on 22K protein display partial cytoplasmic spreading, comparable to that of cells adhering to cell-binding fragments of pFN. Adhesion activity of 22K is not due to contamination with known adhesive proteins of dermal matrices and is not dermal cell type-specific, since two classes of neuronal cells also respond effectively to 22K substrata. DS-PGs from cartilage or skin completely inhibit 22K adhesion activity when the PGs are adsorbed to 22K substrata under conditions prohibiting PGs from binding to substrata directly. Cartilage chondroitin/keratan sulfate proteoglycan at much higher concentrations is only partially inhibitory. Inhibition by DS-PGs is mediated by DS chains binding to 22K. Properties of the cell surface 'receptor' for 22K protein were tested by several approaches. It is not cell surface DS-PG, since: (1) cells unable to produce this proteoglycan class also responded; (2) cells treated with chondroitinase ABC responded equally well; and (3) substrata of proteoglycan-binding platelet factor-4 generated responses from cells that were quantitatively and qualitatively different. A synthetic peptide in the medium containing the Arg-Gly-Asp-Ser (RGDS) sequence completely inhibited responses to 22K substrata. This observation, coupled with sequencing data of 22K protein revealing an Arg-Gly-Ala-Thr sequence at residues 151-154, suggest that 22K protein mediates adhesion by cell surface integrin binding. Therefore, this newly discovered matrix protein from skin may serve as a communication link between the dermal fibroblast cell surface and its extracellular matrix environment.
Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106.
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K
Lewandowska
H U
HU
Choi
L C
LC
Rosenberg
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J
Sasse
P J
PJ
Neame
L A
LA
Culp
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism*; D003871:Dermatan Sulfate / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012867:Skin / Q000378:metabolism
D015815:Cell Adhesion Molecules; D011508:Chondroitin Sulfate Proteoglycans; D011506:Proteins; C032649:dermatan sulfate proteoglycan; D003871:Dermatan Sulfate