Question $2$: $(25$ points$)$

The heat$-$shock response involves a tightly regulated feedback system mediated by HSP$70$ and HSF$1.$ Describe the molecular mechanisms by which HSF$1$ activation is both triggered and later suppressed during and after a heatshock event. Based on this mechanism, hypothesize how a genetic mutation that reduces HSP$70$ expression might impact cellular survival under sustained stress, and propose potential compensatory pathways the cell might activate. $($Predict the consequences of reduced HSP$70$ expression on the heat$-$shock response, including its effect on unfolded protein management and HSF$1$ regulation. Discuss possible compensatory cellular mechanisms, such as upregulation of other chaperone systems or stress response pathways, to mitigate the lack of HSP$70.)$