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p38alpha MAPK is required for contact inhibition.
Dagmar Faust1, Ignacio Dolado, Ana Cuadrado
1Institute of Toxicology, Johannes Gutenberg-University, Obere Zahlbacherstr. 67, 55131 Mainz, Germany.
Oncogene
|July 20, 2005
Summary
Contact inhibition, a crucial cell-cycle control, involves p38alpha mitogen-activated protein kinase (MAPK). This study reveals p38alpha
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cell-cell contacts regulate nontransformed cell proliferation through contact inhibition.
- Intracellular signaling pathways governing contact inhibition are not fully understood.
Purpose of the Study:
- To investigate the role of p38alpha mitogen-activated protein kinase (MAPK) in the contact inhibition signaling cascade.
- To elucidate the mechanistic basis of p38alpha's involvement in fibroblast growth control.
Main Methods:
- Assessed p38alpha activity in confluent versus proliferating human fibroblasts.
- Utilized pharmacological inhibition and genetic knockout (p38alpha-/-) of p38alpha.
- Examined fibroblast saturation density and p27(Kip1) accumulation in wild-type and p38alpha-/- cells.
Main Results:
- p38alpha activity is sustained upon cell-cell contact in confluent fibroblasts.
- Inhibition or absence of p38alpha impairs contact inhibition induction and increases fibroblast saturation density.
- p38alpha deficiency leads to impaired p27(Kip1) accumulation.
Conclusions:
- p38alpha MAPK is a key mediator of contact inhibition in fibroblasts.
- This finding provides a mechanistic link for the proposed tumor-suppressive function of the p38alpha MAPK pathway.