Cell cycle-associated accumulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) in the nuclei of human gingival fibroblasts.
We first confirmed an earlier immunohistochemical study showing that immunoreactive TIMP-1-like protein accumulated in the nuclei of human gingival fibroblasts (Gin-1 cells), reaching a maximum in the S phase of the cell cycle (Li, H., Nishio, K., Yamashita, K., Hayakawa, T. and Hoshino, T. (1995). Nagoya J. Med. Sci. 58, 133-142). Then we isolated this protein from a nuclear extract of Gin-1 cells and demonstrated it to be identical to human recombinant TIMP-1 by western blotting, by a sandwich enzyme immunoassay for TIMP-1 and by an assay for matrix metalloproteinase inhibition. The amount of TIMP-1 in the cytosolic fraction of quiescent Gin-1 cells after stimulation by fetal calf serum increased continuously for 48 hours, whereas that in the nuclear extract showed a maximum at 24 hours (S phase) and significantly decreased thereafter. Gin-1 cells expressed mRNAs for both TIMP-2 and TIMP-3 together with mRNA for TIMP-1. However, neither TIMP-2 nor TIMP-3 proteins seemed to accumulate in the nuclei of Gin-1 cells. These facts strongly suggest that TIMP-1 accumulates specifically in the nuclei of Gin-1 cells in a cell cycle-dependent manner.
Zhao
W Q
WQ
Department of Biochemistry, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.
Li
H
H
Yamashita
K
K
Guo
X K
XK
Hoshino
T
T
Yoshida
S
S
Shinya
T
T
Hayakawa
T
T
D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation; D005881:Gingiva / Q000166:cytology*; D006801:Humans; D020780:Matrix Metalloproteinase 9; D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis* / Q000235:genetics; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis / Q000235:genetics; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000096:biosynthesis / Q000235:genetics
D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D019717:Tissue Inhibitor of Metalloproteinase-3; D019716:Tissue Inhibitor of Metalloproteinase-2; D020780:Matrix Metalloproteinase 9