The chemical brefeldin A is a naturally occurring compound made in fungi that in

Question

The chemical brefeldin A is a naturally occurring compound made in fungi that inhibits the association of COPI coat proteins with membranes specifically in the cis Golgi.

For each of the following, determine if and how the process described would be affected by the addition of brefeldin A to the cells.

Part A: Retrograde transport of proteins containing a KDEL ER retention signal.

Part B: Anterograde transport of proteins that will eventually be secreted from the cell by regulated exocytosis.

Part C: Modification of a glycosyl group on a protein by an enzyme that is only present in the trans Golgi.

Explanation / Answer

part A: retrograde transport occurs from cis golgi to ER, mediated by COP-I coated transport vesicles. when brefedin A is added to the cells, the COPI coat proteins cannot bind to golgi membrane and therefore, cannot form COPI coated vesicles. this would interfere retrograde transport or retrograde transport would be blocked.

part B: anterograde transport occurs from ER to golgi, mediated by COPII coated transport vesicles. since brefeldin A has no affect on COPII coat proteins, anterograde transport occurs without any interference.

part C; since COPI coat proteins have no definite role in modification of glycosyl group on proteins or O-linked glycosylation, this occurs even in presence of brefeldin A.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

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