Materials traffic through the endomembrane system of eukaryotic cells via vesicl
ID: 78084 • Letter: M
Question
Materials traffic through the endomembrane system of eukaryotic cells via vesicles. There are two coat proteins COP I and COP II that assemble vesicles for transport along microtubules. COP I coated vesicles undergo retrograde transport, for example, to move materials from the Golgi back to the ER. COP II coated vesicles undergo anterograde transport to move materials from the ER outward Which motor protein (myosin, kinesin or dynein) interacts with COP I vesicles? Which motor protein interacts with COP II vesicles? Some proteins that traffic in this system contain a KDEL amino acid signal sequence for retention in the ER that interacts with a KDEL receptor protein. Would you expect the KDEL receptor protein to be found associated with COP I or COP II coated vesicles? There had been a long-standing controversy between two different hypotheses about the trafficking of proteins through the Golgi that was resolved in a set of experiments that you studied this semester. What were the two hypotheses? B) Briefly describe the critical experiments that solved this controversy making clear which hypothesis was confirmed. C) What experimental evidence would have confirmed the other hypothesis?Explanation / Answer
Amswer:
60. a. Kinesins (Retrograde)
b. Dynein (Anterograde)
c. COPI
KDEL receptors (multi-pass transmembrane proteins) bind to KDEL sequence of the protein, allowing it to be sorted to the COPI-coated vesicles.
(Since there are more than 1 question, the first full question have been answered according to the rules of Chegg)