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Extracellular matrix and nuclear localization of βig‐h3 in human bladder smooth muscle and fibroblast cells
Author(s) -
Billings Paul C.,
Herrick David J.,
Kucich Umberto,
Engelsberg Beatrice N.,
Abrams William R.,
Macarak Edward J.,
Rosenbloom Joel,
Howard Pamela S.
Publication year - 2000
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/1097-4644(20001101)79:2<261::aid-jcb90>3.0.co;2-#
Subject(s) - extracellular matrix , fibroblast , microbiology and biotechnology , chemistry , extracellular , human bladder , smooth muscle , nuclear matrix , biology , medicine , bladder cancer , endocrinology , biochemistry , dna , cancer , in vitro , chromatin
The extracellular matrix (ECM) plays an essential role in bladder structure and function. In this study, expression of βig‐h3, a recently identified extracellular matrix protein, was investigated in human bladder tissue, and human bladder smooth‐muscle (SMC) and fibroblast cells in vitro. SMCs secreted greater than three times the level of this protein compared with fibroblasts. The relative levels of βig‐h3 mRNA in the two cell types reflected the protein expression. Immunohistochemical analysis demonstrated protein deposition in the ECM as well as cytoplasmic localization and, unexpectedly, nuclei. Anti‐βig‐h3 antibodies also stained the matrix surrounding the detrusor SMCs and nuclei of bladder fibroblasts, SMCs, and urothelium in intact bladder tissue. Western blot analyses of medium and matrix fractions obtained from cells in vitro revealed protein of ∼70–74 kDa, whereas nuclear extracts contained a 65‐kDa reactive protein band. We propose that although this protein is a structural component of bladder ECM, its nuclear localization suggests that it has other regulatory and/or structural functions. J. Cell. Biochem. 79:261–273, 2000. © 2000 Wiley‐Liss, Inc.