TY - JOUR
T1 - Tyrosine phosphorylation of maspin in normal mammary epithelia and breast cancer cells
AU - Odero-Marah, Valerie A.
AU - Khalkhali-Ellis, Zhila
AU - Schneider, Galen B.
AU - Seftor, Elisabeth A.
AU - Seftor, Richard E.B.
AU - Koland, John G.
AU - Hendrix, Mary J.C.
N1 - Funding Information:
This research was funded by NIH/NCI CA75681, the Marilyn Rozeboom Endowment from the Order of the Eastern Star (to M.J.C.H.), and the Holden Comprehensive Cancer Center Seed Grant (to Z.K.E).
PY - 2002
Y1 - 2002
N2 - Maspin is a 42 kDa tumor suppressor protein that belongs to the serine protease inhibitor (serpin) family. It inhibits cell motility and invasion in vitro, and tumor growth and metastasis in nude mice; however, maspin's molecular mechanism of action has remained elusive. Maspin contains several tyrosine residues and we hypothesized that phosphorylation of maspin could play a role in its biological function. Our study reveals that maspin is phosphorylated on tyrosine moiety(ies) in normal mammary epithelial cells endogenously expressing maspin. In addition, transfection of the maspin gene, using either a stable or inducible system into maspin-deficient breast cancer cell lines, yields a protein product that is phosphorylated on tyrosine residue(s). Furthermore, recombinant maspin protein can be tyrosine-phosphorylated by the kinase domain from the epidermal growth factor receptor in vitro. These novel observations suggest that maspin, which deviates from the classical serpin, may be an important signal transduction molecule in its phosphorylated form.
AB - Maspin is a 42 kDa tumor suppressor protein that belongs to the serine protease inhibitor (serpin) family. It inhibits cell motility and invasion in vitro, and tumor growth and metastasis in nude mice; however, maspin's molecular mechanism of action has remained elusive. Maspin contains several tyrosine residues and we hypothesized that phosphorylation of maspin could play a role in its biological function. Our study reveals that maspin is phosphorylated on tyrosine moiety(ies) in normal mammary epithelial cells endogenously expressing maspin. In addition, transfection of the maspin gene, using either a stable or inducible system into maspin-deficient breast cancer cell lines, yields a protein product that is phosphorylated on tyrosine residue(s). Furthermore, recombinant maspin protein can be tyrosine-phosphorylated by the kinase domain from the epidermal growth factor receptor in vitro. These novel observations suggest that maspin, which deviates from the classical serpin, may be an important signal transduction molecule in its phosphorylated form.
KW - Breast cancer
KW - EGF receptor kinase
KW - Ecdysone-inducible system
KW - Maspin
KW - Tyrosine phosphorylation
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U2 - 10.1016/S0006-291X(02)00764-7
DO - 10.1016/S0006-291X(02)00764-7
M3 - Article
C2 - 12127964
AN - SCOPUS:0036375796
VL - 295
SP - 800
EP - 805
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -
