Increased activation of Ras in psoriatic lesions

Area of Science:

• Biochemistry
• Cellular Biology
• Dermatology

Background:

• Ras proteins are key regulators of cell signaling pathways, controlling cell growth and differentiation.
• Ras activation involves a switch from GDP-bound (inactive) to GTP-bound (active) states, crucial for signal transduction.
• Current methods for measuring Ras activation, like radiolabeling, are limited to cell cultures.

Purpose of the Study:

• To adapt and validate an enzyme-based assay for measuring Ras-bound GTP and GDP in human skin samples.
• To quantify the activation state of Ras in normal versus psoriatic human skin.
• To investigate the role of Ras activation in the pathogenesis of psoriasis.

Main Methods:

• Development and application of a non-radioactive, enzyme-based assay to measure Ras-bound GTP and GDP.
• Comparison of the enzymatic method with the traditional [32P]PO4 incorporation method in cultured fibroblasts.
• Analysis of Ras activation in tissue samples from normal and psoriatic human skin.

Main Results:

• The enzymatic method for Ras activation measurement showed comparable results to the [32P]PO4 method in cultured cells.
• In normal human skin, approximately 6% of Ras was in the active GTP-bound state.
• In psoriatic skin lesions, the active GTP-bound Ras increased to 15.4%, while total Ras levels remained similar to normal skin.

Conclusions:

• The developed enzymatic assay provides a rapid and precise method for assessing Ras activation in human skin.
• Psoriatic skin exhibits significantly elevated levels of active GTP-bound Ras compared to normal skin.
• Enhanced Ras signaling is a likely contributor to the hyperproliferative phenotype observed in psoriasis.