Question

1.) HSP27 is upregulated after mitosis is complete and it tends to bind monomers of GFAP. Use this information together with your understadning of the function of chaperone proteins (chaperon protein uses ATP to help proteins fold correctly) in the cell to speculate on the role od HSP27 plays in the cell with respect to GFAP?

Rubric: Logical explanation for why chaperon protein binds to GFAP monomers after cell division is complete.

2.) Specific forms of benign tumors have been shown to migrate more readily when GFAP is phosporylated. These cells are not dividing, they are migrating. Speculate as to why amigrating cell might have hyperphosporylated GFAP?

Rubric: Correct statement on the effect of phosporylation on intermediate filaments and plausible explanation for effect of cell phosporylation on cell migration.

Answer 1

Ans 1) HSP27 is a heat shock protein 27 and is a chaperone of the small heat shock protein which helps in performing functions like thermo-tolerance, apoptosis inhibition, cell development and differentiation regulation along with helping in the process of signal transduction. The GFAP or glial fibrillary acidic protein is an intermediate filament that is expressed in a number of cells within central nervous system and it helps in cell communication and proper communication through the blood brain barrier. It also helps in the process of mitosis. The HSP27 protein plays protective role against oxidative stress, apoptosis and damage of the cytoskeleton. The HSP27 proteins are chaperones which bind to the GFAP and play a very important role in stabilization of the unfolded proteins and help with translocation, degradation and folding. The chaperones help in preventing non specific aggregation and hence is stabilizing the GFAP once the cell division is over.