Proteins and ER.

There’s a serious human disease in which people lack a particular endoplasmic reticulum lumen protein, a chaperone. One therapy that was tried -- on mice, fortunately -- was to engineer a gene of a very similar protein so it contained a complete KDEL sequence that was recognized by the mouse cis-Golgi KDEL-receptor. Again, the modified protein was one which is not normally found in the ER lumen of mice. To carry out the experimental trial, a lot of engineered protein molecules were microinjected into the extracellular fluid of a mouse’s liver (extracellular fluid is the liquid found outside cells). It was taken up into liver cells by endocytosis.

Did the KDEL-protein relieve symptoms of the missing chaperone? If so, how did it do it? If not, why not?

If it did work, how did it get to the ER? If it didn’t work, why didn’t it get to the ER?

Don’t concern yourself about whether this could actually work or not.