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Cellular Signalling Feb 2012R-spondins (RSPOs) are a family of cysteine-rich secreted proteins containing a single thrombospondin type I repeat (TSR) domain. A vast amount of information regarding... (Review)
Review
R-spondins (RSPOs) are a family of cysteine-rich secreted proteins containing a single thrombospondin type I repeat (TSR) domain. A vast amount of information regarding cellular signaling and biological functions of RSPOs has emerged over the last several years, especially with respect to their roles in the activation of the WNT signaling pathway. The identification of several classes of RSPO receptors may indicate that this family of proteins can affect several signaling cascades. Herein, we summarize the current understanding of RSPO signaling and its biological functions, and discuss its potential therapeutic implications to human diseases.
Topics: Amino Acid Sequence; Animals; CD36 Antigens; Cell Proliferation; Crohn Disease; Gene Expression Regulation; Humans; Insulin-Secreting Cells; Intestines; Mice; Molecular Sequence Data; Muscle Development; Osteogenesis; Protein Interaction Domains and Motifs; Protein Isoforms; Stem Cells; Thrombospondins; Wnt Proteins; Wnt Signaling Pathway; beta Catenin
PubMed: 21982879
DOI: 10.1016/j.cellsig.2011.09.023 -
Neural Plasticity 2014Matricellular proteins are secreted, nonstructural proteins that regulate the extracellular matrix (ECM) and interactions between cells through modulation of growth... (Review)
Review
Matricellular proteins are secreted, nonstructural proteins that regulate the extracellular matrix (ECM) and interactions between cells through modulation of growth factor signaling, cell adhesion, migration, and proliferation. Despite being well described in the context of nonneuronal tissues, recent studies have revealed that these molecules may also play instrumental roles in central nervous system (CNS) development and diseases. In this minireview, we discuss the matricellular protein families SPARC (secreted protein acidic and rich in cysteine), Hevin/SC1 (SPARC-like 1), TN-C (Tenascin C), TSP (Thrombospondin), and CCN (CYR61/CTGF/NOV), which are secreted by astrocytes during development. These proteins exhibit a reduced expression in adult CNS but are upregulated in reactive astrocytes following injury or disease, where they are well placed to modulate the repair processes such as tissue remodeling, axon regeneration, glial scar formation, angiogenesis, and rewiring of neural circuitry. Conversely, their reexpression in reactive astrocytes may also lead to detrimental effects and promote the progression of neurodegenerative diseases.
Topics: Animals; Astrocytes; CCN Intercellular Signaling Proteins; Calcium-Binding Proteins; Central Nervous System; Central Nervous System Diseases; Extracellular Matrix; Extracellular Matrix Proteins; Humans; Osteonectin; Tenascin; Thrombospondins
PubMed: 24551460
DOI: 10.1155/2014/321209 -
Scientific Reports Aug 2020R-spondin (RSPO) proteins amplify Wnt signaling and stimulate regeneration in a variety of tissues. To repair tissue in a tissue-specific manner, tissue-targeted RSPO...
R-spondin (RSPO) proteins amplify Wnt signaling and stimulate regeneration in a variety of tissues. To repair tissue in a tissue-specific manner, tissue-targeted RSPO mimetic molecules are desired. Here, we mutated RSPO (RSPO2 F105R/F109A) to eliminate LGR binding while preserving ZNRF3/RNF43 binding and targeted the mutated RSPO to a liver specific receptor, ASGR1. The resulting bi-specific molecule (αASGR1-RSPO2-RA) enhanced Wnt signaling effectively in vitro, and its activity was limited to ASGR1 expressing cells. Systemic administration of αASGR1-RSPO2-RA in mice specifically upregulated Wnt target genes and stimulated cell proliferation in liver but not intestine (which is more responsive to non-targeted RSPO2) in healthy mice, and improved liver function in diseased mice. These results not only suggest that a tissue-specific RSPO mimetic protein can stimulate regeneration in a cell-specific manner, but also provide a blueprint of how a tissue-specific molecule might be constructed for applications in a broader context.
Topics: Animals; Asialoglycoprotein Receptor; Cell Line; Cell Proliferation; Drug Discovery; HEK293 Cells; Humans; Intercellular Signaling Peptides and Proteins; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Receptors, G-Protein-Coupled; Signal Transduction; Thrombospondins; Ubiquitin-Protein Ligases; Wnt Signaling Pathway; beta Catenin
PubMed: 32811902
DOI: 10.1038/s41598-020-70912-3 -
The Journal of Biological Chemistry Oct 2003In addition to its recognition by alpha3beta1 and alpha4beta1 integrins, the N-terminal pentraxin module of thrombospondin-1 is a ligand for alpha6beta1 integrin....
In addition to its recognition by alpha3beta1 and alpha4beta1 integrins, the N-terminal pentraxin module of thrombospondin-1 is a ligand for alpha6beta1 integrin. alpha6beta1 integrin mediates adhesion of human microvascular endothelial and HT-1080 fibrosarcoma cells to immobilized thrombospondin-1 and recombinant N-terminal regions of thrombospondin-1 and thrombospondin-2. alpha6beta1 also mediates chemotaxis of microvascular cells to thrombospondin-1 and thrombospondin-2. Using synthetic peptides, LALERKDHSG was identified as an alpha6beta1-binding sequence in thrombospondin-1. This peptide inhibited alpha6beta1-dependent cell adhesion to thrombospondin-1, thrombospondin-2, and the E8 fragment of murine laminin-1. The Glu residue in this peptide was required for activity, and the corresponding residue (Glu90) in the N-terminal module of thrombospondin-1 was required for its recognition by alpha6beta1, but not by alpha4beta1. alpha6beta1 was also expressed in human umbilical vein endothelial cells; but in these cells, only certain agonists could activate the integrin to recognize thrombospondins. Selective activation of alpha6beta1 integrin in microvascular endothelial cells by the anti-beta1 antibody TS2/16 therefore accounts for their adhesion responses to thrombospondins and explains the distinct functions of alpha4beta1 and alpha6beta1 integrins as thrombospondin receptors in microvascular and large vessel endothelial cells.
Topics: Amino Acid Sequence; Animals; Cell Adhesion; Cell Line; Cell Line, Tumor; Cells, Cultured; Chemotaxis; Dose-Response Relationship, Drug; Endothelium, Vascular; Flow Cytometry; Humans; Integrin alpha6beta1; Laminin; Ligands; Microcirculation; Molecular Sequence Data; Peptides; Precipitin Tests; Protein Structure, Tertiary; Reverse Transcriptase Polymerase Chain Reaction; Sequence Homology, Amino Acid; Thrombospondin 1; Thrombospondins; Umbilical Veins
PubMed: 12909644
DOI: 10.1074/jbc.M302014200 -
International Journal of Molecular... Feb 2021Osteoarthritis (OA) is a slow-progressing joint disease, leading to the degradation and remodeling of the cartilage extracellular matrix (ECM). The usually quiescent...
Osteoarthritis (OA) is a slow-progressing joint disease, leading to the degradation and remodeling of the cartilage extracellular matrix (ECM). The usually quiescent chondrocytes become reactivated and accumulate in cell clusters, become hypertrophic, and intensively produce not only degrading enzymes, but also ECM proteins, like the cartilage oligomeric matrix protein (COMP) and thrombospondin-4 (TSP-4). To date, the functional roles of these newly synthesized proteins in articular cartilage are still elusive. Therefore, we analyzed the involvement of both proteins in OA specific processes in in vitro studies, using porcine chondrocytes, isolated from femoral condyles. The effect of COMP and TSP-4 on chondrocyte migration was investigated in transwell assays and their potential to modulate the chondrocyte phenotype, protein synthesis and matrix formation by immunofluorescence staining and immunoblot. Our results demonstrate that COMP could attract chondrocytes and may contribute to a repopulation of damaged cartilage areas, while TSP-4 did not affect this process. In contrast, both proteins similarly promoted the synthesis and matrix formation of collagen II, IX, XII and proteoglycans, but inhibited that of collagen I and X, resulting in a stabilized chondrocyte phenotype. These data suggest that COMP and TSP-4 activate mechanisms to protect and repair the ECM in articular cartilage.
Topics: Animals; Arthritis, Experimental; Cartilage Oligomeric Matrix Protein; Cartilage, Articular; Chondrocytes; Extracellular Matrix; Female; Osteoarthritis; Swine; Thrombospondins
PubMed: 33668140
DOI: 10.3390/ijms22052242 -
BioMed Research International 2021Thrombospondin 2 (THBS2) acts as oncogenic or tumor suppressive gene in diverse cancers. Here we studied the prognostic and immunological role of THBS2 in colorectal...
OBJECTIVE
Thrombospondin 2 (THBS2) acts as oncogenic or tumor suppressive gene in diverse cancers. Here we studied the prognostic and immunological role of THBS2 in colorectal cancer (CRC) using bioinformatic analysis.
METHODS
The genetic and protein expression of THBS2 in CRC were explored across several databases, including ONCOMINE, GEPIA2, TIMER 2.0, UALCAN and HPA databases. Correlation between THBS2 expression and clinical features in CRC was assessed using UALCAN tool. Prognostic analysis was performed using GEPIA2 and PrognoScan. Immune infiltration correlation with THBS2 in CRC was investigated with TIMER 2.0 and TISIDB. THBS2 binding and correlated genes were analyzed using String, GEPIA2, and TIMER 2.0.
RESULTS
THBS2 was significantly higher in CRC across multiple databases. Age and histological subtype were correlated with THBS2 level. High THBS2 expression correlated with short overall and disease-free survival. THBS2 expression was positively correlated with immune infiltrates in CRC. Moreover, extracellular matrix structural constituent and organization, PI3K-Akt pathway, were involved in the functional mechanisms of THBS2.
CONCLUSIONS
THBS2 correlates with poor prognosis and immune infiltration in CRC. THBS2 may act as a prognostic and immunological biomarker for CRC.
Topics: Biomarkers, Tumor; Colorectal Neoplasms; Computational Biology; Databases, Genetic; Humans; Lymphocytes, Tumor-Infiltrating; Prognosis; Survival Rate; Thrombospondins
PubMed: 34471634
DOI: 10.1155/2021/1124985 -
The Journal of Biological Chemistry Mar 1984The NH2-terminal amino acid sequences of thrombospondin and of a 30,000-Da heparin-binding peptide derived from thrombospondin by treatment with plasmin are identical....
The NH2-terminal amino acid sequences of thrombospondin and of a 30,000-Da heparin-binding peptide derived from thrombospondin by treatment with plasmin are identical. The heparin-binding peptide is homogeneous in size but slightly heterogeneous in charge with the predominant isoelectric points being 6.1 and 5.7. Electron microscopy of tungsten replicas of thrombospondin reveals a tripartite structure resembling a "bola" which is about 60 nm across when fully extended. Each part of the molecule terminates in a globular node or head which disappears upon limited plasmin digestion, suggesting that the heparin-binding peptide is located in the head region. In addition to the heparin-binding peptide, a 20,000-Da peptide also apparently associated with the head region is liberated during proteolysis. The electron micrographs indicate that the legs of the bola-like structure must be folded into an extended, flexible, tertiary structure. These legs, each of about 65,000 Da, appear to be attached near the ends opposite the heads, probably by disulfide bonds. Each leg possesses a tab or protein (approximately 20,000 Da) which juts out from this attachment point.
Topics: Amino Acid Sequence; Blood Platelets; Electrophoresis, Polyacrylamide Gel; Fibrinolysin; Glycoproteins; Humans; Microscopy, Electron; Peptide Fragments; Thrombospondins
PubMed: 6231289
DOI: No ID Found -
The Journal of Biological Chemistry Dec 2005The signature domain of thrombospondins consists of tandem epidermal growth factor-like modules, 13 calcium-binding repeats, and a lectin-like module. Although very...
The signature domain of thrombospondins consists of tandem epidermal growth factor-like modules, 13 calcium-binding repeats, and a lectin-like module. Although very similar, the signature domains of thrombospondin-1 and -2 differ in several potentially important ways from the domains of thrombospondin-3, -4, and -5. We have compared matching recombinant segments representing the signature domains of thrombospondin-2 and -4. In the presence of 2 mM CaCl2, the far UV circular dichroism spectra of thrombospondin-2 and -4 constructs contain a strong negative band at 202 nm, but only the thrombospondin-2 construct has a band at 216 nm. Chelation of calcium shifted the negative bands to lower magnitudes. Titrations of the spectra demonstrated lower cooperativity and affinity for binding of calcium to thrombospondin-4 compared with thrombospondin-2. Atomic absorption spectroscopy demonstrated that the thrombospondin-4 constructs bind seven less calcium than the thrombospondin-2 construct at 0.6 mM CaCl2. In 2 mM CaCl2, the near UV circular dichroism spectra of thrombospondin-2, but not thrombospondin-4, contain a positive band at 292 nm that disappears upon calcium chelation. Intrinsic fluorescence spectra for both proteins were also sensitive to calcium, but the changes were simpler and more marked for thrombospondin-2 than for thrombospondin-4. In differential scanning calorimetry, the thrombospondin-2 construct melted in two distinct transitions at 53.5 and 81.8 degrees C, whereas the first transition for thrombospondin-4 constructs was observed at 63.5 degrees C. Thus, the studies revealed significant differences between the signature domains of thrombospondin-2 and thrombospondin-4 in calcium binding, fine structure, and inter-modular interactions.
Topics: Amino Acid Motifs; Amino Acid Sequence; Animals; Binding Sites; Biophysics; Calcium; Calcium Chloride; Calorimetry, Differential Scanning; Cell Line; Chelating Agents; Circular Dichroism; Cloning, Molecular; Dose-Response Relationship, Drug; Epidermal Growth Factor; Humans; Insecta; Ions; Lectins; Magnetic Resonance Spectroscopy; Molecular Sequence Data; Polymorphism, Genetic; Protein Binding; Protein Structure, Tertiary; Recombinant Proteins; Sequence Homology, Amino Acid; Spectrometry, Fluorescence; Spectrophotometry; Spectrophotometry, Atomic; Temperature; Thrombospondins; Tryptophan; Ultraviolet Rays
PubMed: 16246837
DOI: 10.1074/jbc.M504696200 -
International Journal of Molecular... Feb 2024In intrahepatic cholangiocarcinoma (iCCA), thrombospondin 1 (THBS1) and 2 (THBS2) are soluble mediators released in the tumor microenvironment (TME) that contribute to...
In intrahepatic cholangiocarcinoma (iCCA), thrombospondin 1 (THBS1) and 2 (THBS2) are soluble mediators released in the tumor microenvironment (TME) that contribute to the metastatic spreading of iCCA cells via a lymphatic network by the trans-differentiation of vascular endothelial cells to a lymphatic-like phenotype. To study the direct role of THBS1 and THBS2 on the iCCA cells, well-established epithelial (HuCCT-1) and mesenchymal (CCLP1) iCCA cell lines were subjected to recombinant human THBS1 and THBS2 (rhTHBS1, rhTHBS2) for cellular function assays. Cell growth, cell adhesion, migration, and invasion were all enhanced in both CCLP1 and HuCCT-1 cells by the treatment with either rhTHBS1 or rhTHBS2, although they showed some variability in their intensity of speeding up cellular processes. rhTHBS2 was more intense in inducing invasiveness and in committing the HuCCT-1 cells to a mesenchymal-like phenotype and was therefore a stronger enhancer of the malignant behavior of iCCA cells compared to rhTHBS1. Our data extend the role of THBS1 and THBS2, which are not only able to hinder the vascular network and promote tumor-associated lymphangiogenesis but also exacerbate the malignant behavior of the iCCA cells.
Topics: Humans; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Cell Proliferation; Cholangiocarcinoma; Endothelial Cells; Thrombospondin 1; Tumor Microenvironment; Thrombospondins
PubMed: 38339060
DOI: 10.3390/ijms25031782 -
ELife Dec 2019Previous studies demonstrated importance of C-mannosylation for efficient protein secretion. To study its impact on protein folding and stability, we analyzed both...
Previous studies demonstrated importance of C-mannosylation for efficient protein secretion. To study its impact on protein folding and stability, we analyzed both C-mannosylated and non-C-mannosylated thrombospondin type 1 repeats (TSRs) of netrin receptor UNC-5. In absence of C-mannosylation, UNC-5 TSRs could only be obtained at low temperature and a significant proportion displayed incorrect intermolecular disulfide bridging, which was hardly observed when C-mannosylated. Glycosylated TSRs exhibited higher resistance to thermal and reductive denaturation processes, and the presence of C-mannoses promoted the oxidative folding of a reduced and denatured TSR in vitro. Molecular dynamics simulations supported the experimental studies and showed that C-mannoses can be involved in intramolecular hydrogen bonding and limit the flexibility of the TSR tryptophan-arginine ladder. We propose that in the endoplasmic reticulum folding process, C-mannoses orient the underlying tryptophan residues and facilitate the formation of the tryptophan-arginine ladder, thereby influencing the positioning of cysteines and disulfide bridging.
Topics: Animals; Arginine; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cysteine; Disulfides; Drosophila melanogaster; Endoplasmic Reticulum; Glycosylation; Hydrogen Bonding; Mannose; Membrane Proteins; Molecular Dynamics Simulation; Protein Conformation; Protein Folding; Receptors, Cell Surface; Thrombospondins; Tryptophan
PubMed: 31868591
DOI: 10.7554/eLife.52978