Syndecan 3: a member of the syndecan family of membrane-intercalated proteoglycans that is expressed in high amounts at the onset of chicken limb cartilage differentiation.
A partial cDNA that encodes a newly discovered member of the syndecan family of integral membrane proteoglycans, which we have termed syndecan 3, has been isolated from an embryonic chicken limb bud cDNA library. Syndecan 3 is distinct from but structurally related to syndecan and fibroglycan, two previously characterized members of this family of membrane-intercalated proteoglycans. Syndecan 3 contains a cytoplasmic domain potentially associated with the cytoskeleton that is 85% identical in amino acid sequence to the cytoplasmic domain of syndecan. Syndecan 3 also possesses a hydrophobic transmembrane domain and an extracellular domain containing several clustered potential glycosaminoglycan attachment sites. Like syndecan, the ectodomain of syndecan 3 has a single dibasic protease-susceptible site adjacent to the transmembrane domain, which might be involved in shedding the ectodomain from the cell surface. A striking feature of syndecan 3 is an extensive (182 amino acid) threonine, serine, and proline (T+S+P)-rich domain that closely resembles T+S+P-rich regions in several mucin-like proteins in which O-linked oligosaccharides are bound to the threonine and serine residues. Syndecan 3 is expressed in high amounts during a critical phase of chicken limb chondrogenesis in which limb mesenchymal cells condense, round up, and interact with one another before depositing a cartilage matrix. The multiple functional domains of syndecan 3 provide potential sites for mediating the adhesive cell-matrix interactions and cytoskeletal reorganization involved in this critical condensation process.
Gould
S E
SE
Department of Anatomy, School of Medicine, University of Connecticut Health Center, Farmington 06030.
Upholt
W B
WB
Kosher
R A
RA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002356:Cartilage / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005121:Extremities / Q000196:embryology; D005786:Gene Expression Regulation; D015723:Gene Library; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D011509:Proteoglycans / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D053670:Syndecan-3; D053667:Syndecans
D008562:Membrane Glycoproteins; D009838:Oligodeoxyribonucleotides; D011509:Proteoglycans; D053670:Syndecan-3; D053667:Syndecans; D004247:DNA