Uncovering the Mechanism of ICI-Mediated Estrogen Receptor-Alpha Degradation

摘要

A cytoplasmic ER mutant (cER), lacking its NLS domain, is completely resistant to ICI-mediated degradation. The inability of ICI to degrade cER is not due to an inability of cER to bind ICI. Furthermore, the resistance phenotype is independent of both length of treatment with ligand and dose of ICI that is administered. The NLS domain may serve as a region of interaction with other proteins that assist in the degradation process. If this statement is true, it is unlikely that keratin 18 (K18), a protein previously reported to be critical for ICI-mediated degradation of ER, is one of these interacting proteins. It appears that K18 can interact with both full-length wild-type ER and with cER lacking the NLS. Therefore, the inability of ICI to degrade cER is not likely due to an inability of cER to interact with K18.