Final answer:
Hsp70 chaperonins bind to any unfolded protein region, particularly exposing hydrophobic amino acids, assisting in proper protein folding. The cell increases Hsp70 activity in response to heat shock to prevent aggregation and ensure protein functionality. These chaperones are essential for maintaining cellular function under stress.
Step-by-step explanation:
Heat shock protein 70 (Hsp70) chaperonins play an essential role in protein folding and are critical for cellular function, especially under stress conditions. Hsp70 binds to any unfolded protein region; specifically, it recognizes and binds to hydrophobic (non-polar) amino acid sequences that are exposed when a protein is not correctly folded. During stressful conditions, such as heat shock, incorrect folding can occur. Hsp70, along with other chaperones, assists in preventing aggregation by binding to these exposed segments, facilitating the correct refolding of proteins, or targeting them for degradation if they are irreversibly damaged.
Cells respond to heat shock or stress by increasing the activity of heat shock proteins, which includes a rise in transcription and activation of genes coding for these proteins. This elevated activity helps to protect the cells from the aggregation of misfolded proteins, which can occur during high temperatures or other abnormal conditions like changes in pH or adding certain chemicals. Protein folding is crucial to a protein's function, and Hsp70 is an essential player in maintaining cellular homeostasis under stress.