Imagine you have engineered a set of genes, each encoding aprotein with a pair o

Question

Imagine you have engineered a set of genes, each encoding aprotein with a pair of conflicting signal sequences that specifydifferent compartments. If the genes were expressed in a cell,predict which signal would win out for the following combinations.Explain your reasoning.

A) Signals for import into the nucleus and import into theER.

B) Signals for import into peroxisomes and import into theER.

C) Signals for import into mitochondria and retention in ER (ie,the KDEL signal for retrieval from Golgi to ER). (In this case, youare to assume that we have specially engineered the protein to havea KDEL sequence, and a mitochondrial import sequence, but noamino-terminal signal sequence.)

Explanation / Answer

1) It would end up in the ER, since proteins imported into theER are imported co-translationally, while those imported into thenucleus are imported post-translationally. 2) Same as above: the ER. 3) I'm unfamiliar with the KDEL sequence, but try to figure itout by looking at which import signals illicit a co- or post-translational response. Many signals also require more than oneportion to work (for example, an ER stop-transfer sequence is notsufficient to get a protein into the ER. It also needs astart-transfer sequence).

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.