Related Experiment Videos
Mek1 alters epidermal growth and differentiation
Florence A Scholl1, Phillip A Dumesic, Paul A Khavari
1VA Palo Alto Healthcare System, Palo Alto, California 94305, USA.
Cancer Research
|September 3, 2004
Summary
Mek1 and Mek2 kinases activate ERK. Mek1, but not Mek2, drives epidermal hyperplasia and suppresses differentiation, mimicking neoplasia, even without kinase activity.
Area of Science:
- Molecular biology
- Cell signaling
- Dermatology
Background:
- Mek1 and Mek2 are homologous kinases downstream of Ras/Raf, activating ERK.
- Ras/Raf signaling in epidermis promotes hyperplasia via multiple effectors.
- The specific roles of Mek1 and Mek2 in mediating Ras/Raf effects are not fully understood.
Purpose of the Study:
- To investigate the distinct roles of Mek1 and Mek2 in epidermal signaling.
- To determine the extent to which Mek kinases mediate Ras/Raf-driven epidermal hyperplasia.
- To elucidate the mechanism by which Mek1 promotes epidermal proliferation.
Main Methods:
- Expression of inducible Mek1 and Mek2 in transgenic murine and human epidermis.
- Analysis of ERK phosphorylation levels.
- Assessment of epidermal proliferation, differentiation, and integrin expression.
- Utilizing a kinase-dead Mek1 mutant.
Main Results:
- Both Mek1 and Mek2 induced ERK phosphorylation.
- Mek1, but not Mek2, replicated Ras/Raf effects: increased proliferation, integrin expression, and suppressed differentiation.
- A kinase-dead Mek1 mutant retained the ability to promote epidermal proliferation, independent of ERK phosphorylation.
Conclusions:
- Mek1 is sufficient to induce the proliferative epithelial phenotype characteristic of neoplasia.
- Mek1-driven epidermal proliferation can occur independently of its kinase activity.
- Mek1 possesses functions beyond ERK activation that contribute to epidermal hyperplasia.