Connective tissue growth factor (CCN2) is a matricellular preproprotein controlled by proteolytic activation
| Autor: | Else Marie Valbjørn Hagelin, Jianhua Wang, Ashish K. Gadicherla, Ole Jørgen Kaasbøll, Vivi Talstad Monsen, Håvard Attramadal, Meng-Qiu Dong |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Cell signaling Recombinant Fusion Proteins medicine.medical_treatment Connective tissue CHO Cells Biochemistry Fibroblast migration Mice Nephroblastoma Overexpressed Protein 03 medical and health sciences Cricetulus 0302 clinical medicine Protein Domains Cell Line Tumor medicine Animals Humans CCN protein Protein Precursors Molecular Biology Thrombospondin integumentary system Chemistry Growth factor Matricellular protein Connective Tissue Growth Factor Cell Biology Immunoglobulin Fc Fragments Rats Cell biology CTGF RAW 264.7 Cells 030104 developmental biology medicine.anatomical_structure Immunoglobulin G 030220 oncology & carcinogenesis Proteolysis Protein Structure and Folding Cysteine-Rich Protein 61 |
| Zdroj: | Journal of Biological Chemistry. 293:17953-17970 |
| ISSN: | 0021-9258 |
| Popis: | Connective tissue growth factor (CTGF; now often referred to as CCN2) is a secreted protein predominantly expressed during development, in various pathological conditions that involve enhanced fibrogenesis and tissue fibrosis, and in several cancers and is currently an emerging target in several early-phase clinical trials. Tissues containing high CCN2 activities often display smaller degradation products of full-length CCN2 (FL-CCN2). Interpretation of these observations is complicated by the fact that a uniform protein structure that defines biologically active CCN2 has not yet been resolved. Here, using DG44 CHO cells engineered to produce and secrete FL-CCN2 and cell signaling and cell physiological activity assays, we demonstrate that FL-CCN2 is itself an inactive precursor and that a proteolytic fragment comprising domains III (thrombospondin type 1 repeat) and IV (cystine knot) appears to convey all biologically relevant activities of CCN2. In congruence with these findings, purified FL-CCN2 could be cleaved and activated following incubation with matrix metalloproteinase activities. Furthermore, the C-terminal fragment of CCN2 (domains III and IV) also formed homodimers that were ∼20-fold more potent than the monomeric form in activating intracellular phosphokinase cascades. The homodimer elicited activation of fibroblast migration, stimulated assembly of focal adhesion complexes, enhanced RANKL-induced osteoclast differentiation of RAW264.7 cells, and promoted mammosphere formation of MCF-7 mammary cancer cells. In conclusion, CCN2 is synthesized and secreted as a preproprotein that is autoinhibited by its two N-terminal domains and requires proteolytic processing and homodimerization to become fully biologically active. |
| Databáze: | OpenAIRE |
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