Proteomic profiling of fibroblasts reveals a modulating effect of extracellular calumenin on the organization of the actin cytoskeleton.
CREC proteins constitute a family of EF-hand calcium binding proteins localized to the secretory pathway. Calumenin is the only member known to be secreted. Recently, it was shown that thrombin-activated thrombocytes liberate calumenin, which also is found in atherosclerotic lesions but not in normal vasculature. To study the possible effects of calumenin extracellularly, we used proteomic profiling of fibroblasts cultured in absence and in presence of calumenin. Using 2-DE and MS/MS, we show that normal fibroblasts contain several 28-29-kDa N-terminal and a 16-kDa C-terminal fragment of beta- or gamma-actin. Extracellularly added calumenin decreases the levels of both the N-terminal and C-terminal actin fragments, and, in addition, decreases the expression level of septin 2, which interacts with the actin cytoskeleton and is involved in cytokinesis. Labeling of S-phase fibroblasts with bromo-2'deoxy-uridine indicates that calumenin added to the medium also modulates the cell cycle. Our study thus indicates that calumenin may have an autocrine or a paracrine effect on the cells in its vicinity, and, therefore, may be involved in the pathophysiology of thrombosis or in wound healing.
Ostergaard
Morten
M
Institute of Medical Biochemistry, Ole Worms Allé, University of Aarhus, Denmark.
Hansen
Gry A W
GA
Vorum
Henrik
H
Honoré
Bent
B
D000199:Actins / Q000378:metabolism*; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D018929:Cell Culture Techniques; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects*; D006207:Half-Life; D006801:Humans; D013058:Mass Spectrometry; D010449:Peptide Mapping; D040901:Proteomics; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D016622:Silver Staining
D000199:Actins; C510527:CALU protein, human; D002135:Calcium-Binding Proteins; D003470:Culture Media; D011994:Recombinant Proteins