Thus cells trisomic for chromosome 21 bind more interferon. Interferon internalized is degraded. This however may not be the case with IFN gamma. In this case internalization does lead to biological activity. The IFN gamma receptor gene is located on chromosome 6.This receptor is a glycoprotein of 95kd.
Interferons exert their effort by activating a signal transduction pathway.
A signal transduction pathway consists of a cascade of reactions that begins when a signaling molecule binds to a receptor that spans the membrane. The binding causes that part of the receptor that lies within the cell to convey commands to other molecules in the cells. The end product is the transcription of novel mRNAs that code for proteins that interfere with viral replication of some other function of the cell. The induction by the interferons does not involve what are known as second messages. The binding of the interferons activates a newly identified class of enzymes known as the Janus kinases.