The link domain is a hyaluronan (HA)-binding domain. It functions to mediate adhesive interactions during inflammatory leukocyte homing and tumor metastasis. It is found in the CD44 receptor and in human TSG-6. TSG-6 is the protein product of the tumor necrosis factor-stimulated gene-6. TSG-6 has a strong anti-inflammatory effect in models of acute inflammation and autoimmune arthritis and plays an essential role in female fertility. This group also contains the link domains of the chondroitin sulfate proteoglycan core proteins (CSPG) including aggrecan, versican, neurocan, and brevican and the link domains of the vertebrate HAPLN (HA and proteoglycan binding link) protein family. In cartilage, aggrecan forms cartilage link protein stabilized aggregates with HA. These aggregates contribute to the tissue's load bearing properties. Aggregates in which other CSPGs substitute for aggregan might contribute to the structural integrity of many different tissues. Members of the vertebrate HPLN gene family are physically linked adjacent to CSPG genes. TSG-6 contains a single link module which supports high affinity binding with HA. The functional HA-binding domain of CD44 is an extended domain comprised of a link module flanked with N-and C- extensions. These extensions are essential for folding and functional activity. CSPGs are characterized by an N-terminal globular domain (G1 domain) containing two contiguous link modules (modules 1 and 2). Both link modules of the G1 domain of the CSPG aggrecan are involved in interaction with HA. Aggrecan in addition contains a second globular domain (G2) which contains link modules 3 and 4 which lack HA-binding activity. HAPLNs contain two contiguous link modules.

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                ....*....|....*....|....*....|....*....|....*....|...
gi 48255943  26 ITCRFAGVFHVEKNGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:cd03516   1 ITCRIMGVFLVEKNGRYSLNFTEAKEACRALGLTLASKAQVETALKFGFETCR 53

This domain is a hyaluronan (HA)-binding domain. It is found in CD44 receptor and mediates adhesive interactions during inflammatory leukocyte homing and tumor metastasis. It also plays an important role in arteriogenesis. The functional HA-binding domain of CD44 is an extended domain comprised of a single link module flanked with N-and C- extensions. These extensions are essential for folding and for functional activity. This group also contains the cell surface retention sequence (CRS) binding protein-1 (CRSBP-1) and lymph vessel endothelial receptor-1 (LYVE-1). CRSBP-1 is a cell surface binding protein for the CRS motif of PDGF-BB (platelet-derived growth factor-BB) and is responsible for the cell surface retention of PDGF-BB in SSV-transformed cells. CRSBP-1 may play a role in autocrine regulation of cell growth mediated by CRS containing growth regulators. LYVE-1 is preferentially expressed on the lymphatic endothelium and is used as a molecular marker for the detection and characterization of lymphatic vessels in tumors.

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                ....*....|....*....|....*....|....*....|....*....|...
gi 48255943  26 ITCRFAGVFHVEKNGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:cd03516   1 ITCRIMGVFLVEKNGRYSLNFTEAKEACRALGLTLASKAQVETALKFGFETCR 53

Extracellular link domain;

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                  ....*....|....*....|....*....|....*....|....*..
gi 48255943    32 GVFHVEKNGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:pfam00193   1 GVFHLESPGRYKLTFQEAQAACAALGATLATPEQLYAAWKAGLDTCD 47

This domain is a hyaluronan (HA)-binding domain. It is found in CD44 receptor and mediates adhesive interactions during inflammatory leukocyte homing and tumor metastasis. It also plays an important role in arteriogenesis. The functional HA-binding domain of CD44 is an extended domain comprised of a single link module flanked with N-and C- extensions. These extensions are essential for folding and for functional activity. This group also contains the cell surface retention sequence (CRS) binding protein-1 (CRSBP-1) and lymph vessel endothelial receptor-1 (LYVE-1). CRSBP-1 is a cell surface binding protein for the CRS motif of PDGF-BB (platelet-derived growth factor-BB) and is responsible for the cell surface retention of PDGF-BB in SSV-transformed cells. CRSBP-1 may play a role in autocrine regulation of cell growth mediated by CRS containing growth regulators. LYVE-1 is preferentially expressed on the lymphatic endothelium and is used as a molecular marker for the detection and characterization of lymphatic vessels in tumors.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 48255943  26 ITCRFAGVFHVEKNGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:cd03516   1 ITCRIMGVFLVEKNGRYSLNFTEAKEACRALGLTLASKAQVETALKFGFETCR 53

The link domain is a hyaluronan (HA)-binding domain. It functions to mediate adhesive interactions during inflammatory leukocyte homing and tumor metastasis. It is found in the CD44 receptor and in human TSG-6. TSG-6 is the protein product of the tumor necrosis factor-stimulated gene-6. TSG-6 has a strong anti-inflammatory effect in models of acute inflammation and autoimmune arthritis and plays an essential role in female fertility. This group also contains the link domains of the chondroitin sulfate proteoglycan core proteins (CSPG) including aggrecan, versican, neurocan, and brevican and the link domains of the vertebrate HAPLN (HA and proteoglycan binding link) protein family. In cartilage, aggrecan forms cartilage link protein stabilized aggregates with HA. These aggregates contribute to the tissue's load bearing properties. Aggregates in which other CSPGs substitute for aggregan might contribute to the structural integrity of many different tissues. Members of the vertebrate HPLN gene family are physically linked adjacent to CSPG genes. TSG-6 contains a single link module which supports high affinity binding with HA. The functional HA-binding domain of CD44 is an extended domain comprised of a link module flanked with N-and C- extensions. These extensions are essential for folding and functional activity. CSPGs are characterized by an N-terminal globular domain (G1 domain) containing two contiguous link modules (modules 1 and 2). Both link modules of the G1 domain of the CSPG aggrecan are involved in interaction with HA. Aggrecan in addition contains a second globular domain (G2) which contains link modules 3 and 4 which lack HA-binding activity. HAPLNs contain two contiguous link modules.

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                ....*....|....*....|....*....|....*....|....*...
gi 48255943  32 GVFHVEK-NGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:cd01102   1 VVFHLESqNGRYKLTFAEAALACKARGAHLATPGQLEAAWQDGFDVCT 48

This is the extracellular link domain of the type found in human TSG-6. The link domain is a hyaluronan (HA)-binding domain. TSG-6 is the protein product of tumor necrosis factor-stimulated gene-6. TSG-6 is up-regulated in inflammatory lesions and in the ovary during ovulation. It has a strong anti-inflammatory and chondroprotective effect in models of acute inflammation and autoimmune arthritis and plays an essential role in female fertility. Also included in this group are the stabilins: stabilin-1 (FEEL-1, CLEVER-1) and stabilin-2 (FEEL-2). Stabilin-2 functions as the major liver and lymph node-scavenging receptor for HA and related glycosaminoglycans. Stabilin-2 is a scavenger receptor with a broad range of ligands including advanced glycation end (AGE) products, acetylated low density lipoprotein and procollagen peptides. In contrast, stabilin-1 does not bind HA, but binds acetylated low density lipoprotein and AGEs with lower affinity. As AGEs accumulate in vascular tissues during aging and diabetes, these receptors may be implicated in the pathologies of these states. Both stabilins are present in the early endocytic pathway in hepatic sinusoidal epithelium associating with clathrin/AP-2. Stabilin-1 is expressed in macrophages. Stabilin-2 is absent from the latter. In macrophages: stabilin-1 is involved in trafficking between early/sorting endosomes and the trans-Golgi network. Stabilin-1 has also been implicated in angiogenesis and possibly leucocyte trafficking. Both stabilins bind gram-positive and gram-negative bacteria. TSG-6 and stabilins contain a single link module which supports high affinity binding to HA.

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                ....*....|....*....|....*....|....*....|....*...
gi 48255943  32 GVFHVE-KNGRYSISRTEAADLCKAFNSTLPTMAQMEKALSIGFETCS 78
Cdd:cd03515   1 GVFHLRsRSGKYKLTYTEAKAACEAEGAHLATYSQLSAAQQLGFHLCA 48