TY - JOUR
T1 - Trophinin-mediated cell adhesion induces apoptosis of human endometrial epithelial cells through PKC-δ
AU - Tamura, Naoaki
AU - Sugihara, Kazuhiro
AU - Akama, Tomoya O.
AU - Fukuda, Michiko N.
N1 - Funding Information:
bands were visualized using ECL reagent followed by exposure to The authors thank Drs. Guy Salvesen and Ze’ev Ronai for their X-ray film. Immunoblotting for FAS and PKC-delta was carried critical reading the manuscript, Dr. Elise Lamar for her excellent out as described for trophinin. Dilutions of first antibodies were: editing and Merryl Mathew for technical assistance. This study anti-β-tubulin (1:1,000), anti-Lamin A/C (1:1,000), anti-FAS has been supported by the grant DoD prostate cancer research (1:1,000) and anti-PKC d (1:1,000). grant W81XWH040917. Subcellular fractionation. Cytoplasmic and nuclear frac- tions were prepared as described in reference 41 and 42. Briefly, SNG-M cells grown in 10 cm dishes were scraped with a rubber policeman and washed with PBS. Cells were suspended in 2 ml
PY - 2011/1/1
Y1 - 2011/1/1
N2 - Trophinin is an intrinsic membrane protein expressed in trophectoderm cells of embryos and in uterine epithelial cells. Trophinin potentially mediates apical cell adhesion at human embryo implantation sites through trophinin-trophinin binding in these two cell types. Trophinin-mediated cell adhesion activates trophectoderm cells for invasion, whereas the effect of adhesion on maternal side is not known. We show that addition of GWRQ peptide, a previously established peptide that mimics trophinin-mediated cell adhesion, to human endometrial epithelial cells expressing trophinin induces their apoptosis. FAS involvement was excluded, as GWRQ did not bind to FAS, and FAS knockdown did not alter GWRQ-induced apoptosis. Immunoblotting analyses of protein kinases revealed an elevation of PKC-δ protein in GWRQ-bound endometrial epithelial cells. In the absence of GWRQ, PKC-δ associated with trophinin and remained cytoplasmic, but after GWRQ binding to the trophinin extracellular domain, PKC-δ became tyrosine phosphorylated, dissociated from trophinin and entered the nucleus. In PKC-δ knockdown endometrial cells, GWRQ did not induce apoptosis. These results suggest that trophinin-mediated cell adhesion functions as a molecular switch to induce apoptosis through the PKC-δ pathway in endometrial epithelial cells. Thus, trophinin-mediated induction of apoptosis of endometrial epithelial cells, which function as a barrier to embryo invasion, allows trophoblast invasion of maternal tissue and embryo implantation in humans.
AB - Trophinin is an intrinsic membrane protein expressed in trophectoderm cells of embryos and in uterine epithelial cells. Trophinin potentially mediates apical cell adhesion at human embryo implantation sites through trophinin-trophinin binding in these two cell types. Trophinin-mediated cell adhesion activates trophectoderm cells for invasion, whereas the effect of adhesion on maternal side is not known. We show that addition of GWRQ peptide, a previously established peptide that mimics trophinin-mediated cell adhesion, to human endometrial epithelial cells expressing trophinin induces their apoptosis. FAS involvement was excluded, as GWRQ did not bind to FAS, and FAS knockdown did not alter GWRQ-induced apoptosis. Immunoblotting analyses of protein kinases revealed an elevation of PKC-δ protein in GWRQ-bound endometrial epithelial cells. In the absence of GWRQ, PKC-δ associated with trophinin and remained cytoplasmic, but after GWRQ binding to the trophinin extracellular domain, PKC-δ became tyrosine phosphorylated, dissociated from trophinin and entered the nucleus. In PKC-δ knockdown endometrial cells, GWRQ did not induce apoptosis. These results suggest that trophinin-mediated cell adhesion functions as a molecular switch to induce apoptosis through the PKC-δ pathway in endometrial epithelial cells. Thus, trophinin-mediated induction of apoptosis of endometrial epithelial cells, which function as a barrier to embryo invasion, allows trophoblast invasion of maternal tissue and embryo implantation in humans.
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U2 - 10.4161/cc.10.1.14448
DO - 10.4161/cc.10.1.14448
M3 - Article
C2 - 21191175
AN - SCOPUS:78650847137
SN - 1538-4101
VL - 10
SP - 135
EP - 143
JO - Cell Cycle
JF - Cell Cycle
IS - 1
ER -