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Proteomic profiling of fibroblasts reveals a modulating effect of extracellular calumenin on the organization of the actin cytoskeleton
Author(s) -
Østergaard Morten,
Hansen Gry A.W.,
Vorum Henrik,
Honoré Bent
Publication year - 2006
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200500686
Subject(s) - microbiology and biotechnology , actin cytoskeleton , actin , cytoskeleton , cytokinesis , biology , chemistry , biochemistry , cell , cell division
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 β‐ or γ‐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.