Activation of Lyn Tyrosine Kinase through Decreased Membrane Cholesterol Levels During a Change in its Membrane Distribution upon Cell Detachment [Cell Biology]

August 7th, 2014 by Morinaga, T., Abe, K., Nakayama, Y., Yamaguchi, N.,

Cellular membranes, which can serve as scaffolds for signal transduction, dynamically change their characteristics upon cell detachment. Src-family kinases undergo posttranslational lipid modification and are involved in a wide range of signaling events at the plasma membrane, such as cell proliferation, cell adhesion and survival. Previously, we showed the differential membrane distributions among the members of Src-family kinases by sucrose density gradient fractionation. However, little is known about the regulation of the membrane distribution of Src-family kinases upon cell detachment. Here we show that cell detachment shifts the main peak of the membrane distribution of Lyn, a member of Src-family kinase, from the low-density to the high-density membrane fractions and enhances the kinase activity of Lyn. The change in Lyn distribution upon cell detachment involves both dynamin activity and a decrease in membrane cholesterol. Cell detachment activates Lyn through decreased membrane cholesterol levels during a change in its membrane distribution. Furthermore, cholesterol incorporation decreases Lyn activity and reduces the viability of suspension cells. These results suggest that cell detachment-induced Lyn activation through the change in the membrane distribution of Lyn plays an important role in survival of suspension cells.
  • Posted in Journal of Biological Chemistry, Publications
  • Comments Off on Activation of Lyn Tyrosine Kinase through Decreased Membrane Cholesterol Levels During a Change in its Membrane Distribution upon Cell Detachment [Cell Biology]