November 6, 2012

It is Election Day here in the US, which means that some of us need stress relief until the results are tallied. So, maybe you can imagine the graceful membrane dynamics of a cell and let their lava-lamp-like groove lull you into a happy place. Today’s image is from a paper describing the regulation of caveola biogenesis.

Caveolae are small invaginations on a cell’s plasma membrane that play important roles in cell signaling and endocytosis (the uptake of material into a cell). Caveolae depend on proteins called caveolins, but the details of caveola biogenesis are not completely understood. A recent paper describes results showing the importance of phosphorylation of Caveolin-1 (Cav1) in the formation of caveolae. Phosphorylation is the addition of a phosphate group to a protein, which functions as a molecular switch to change the protein’s activity. Joshi and colleagues found that the phosphorylation of Cav1 induces a feedback loop that links together mechanical stress on the cell, caveola biogenesis, and focal adhesion regulation at the cell’s membrane. These results place Cav1 on a list of critical proteins that help a cell respond to mechanical stress. In the images above, mutations of Cav1 that mimic phosphorylation (Cav1Y14R and Cav1Y14D) cause the formation of more caveolae and caveolae clusters (arrows and asterisks) than control cells (Cav1WT).

Joshi, B., Bastiani, M., Strugnell, S., Boscher, C., Parton, R., & Nabi, I. (2012). Phosphocaveolin-1 is a mechanotransducer that induces caveola biogenesis via Egr1 transcriptional regulation originally published in the Journal of Cell Biology, 199 (3), 425-435 DOI: 10.1083/jcb.201207089