Question

What are the 2 methods of IRE1 activation? What happens once it is activated?

Answer 1

IRE1 has two methods of activation: ubiquitin-dependent activation and tyrosine kinase activation. Once it is activated, IRE1 is involved in the unfolded protein response pathway.

Step-by-step explanation:

The two methods of IRE1 activation are:

1. Ubiquitin-dependent activation: In this method, an ubiquitin molecule is activated by ATP hydrolysis and binds to an ubiquitin-activating enzyme. The ubiquitin is then transferred to an ubiquitin-conjugating enzyme, and eventually attaches to the protein destined for destruction.
2. Tyrosine kinase activation: This method involves the activation of a tyrosine kinase enzyme, which leads to the exchange of GDP for GTP, the formation of receptor dimers, and internalization of the insulin molecule in the cytoplasm.

Once IRE1 is activated, it is involved in the unfolded protein response (UPR), a cellular stress response pathway. IRE1 acts as an endoribonuclease, cleaving a specific mRNA to produce an active transcription factor. This transcription factor then activates the expression of genes involved in the UPR, such as chaperones, folding enzymes, and ER-associated degradation components.