5 A) Which of the following statements about apical and basolateral protein sorting is FALSE?
Transcytosis is a mechanism for the movement of basolaterally secreted proteins to the apical membrane.
Infection of epithelial cells with specific viral proteins has helped elucidate the mechanisms of polarized protein secretion.
GPI-linked proteins are sorted specifically to the apical membrane of most polarized epithelial cells.
Vesicles that bud from the trans-Golgi network travel specifically to the apical membrane.
5 B) How does lysosomal pH contribute to lysosomal protein sorting?
Lysosomal proteins only properly fold at the acidic pH found in the lysosome.
Acidic pH is required for fusion of clathrin-coated vesicles with the lysosomal membrane.
Clathrin/AP1 vesicles that travel to the lysosome have a high affinity for lysosomal membranes due to their low pH.
The mannose-6-phosphate receptor has altered affinity for M6P under acidic pH conditions.
5 A) Which of the following statements about apical and basolateral protein sorting is FALSE?
Transcytosis is a mechanism for the movement of basolaterally secreted proteins to the apical membrane.
Infection of epithelial cells with specific viral proteins has helped elucidate the mechanisms of polarized protein secretion.
GPI-linked proteins are sorted specifically to the apical membrane of most polarized epithelial cells.
Vesicles that bud from the trans-Golgi network travel specifically to the apical membrane.
5 B) How does lysosomal pH contribute to lysosomal protein sorting?
Lysosomal proteins only properly fold at the acidic pH found in the lysosome.
Acidic pH is required for fusion of clathrin-coated vesicles with the lysosomal membrane.
Clathrin/AP1 vesicles that travel to the lysosome have a high affinity for lysosomal membranes due to their low pH.
The mannose-6-phosphate receptor has altered affinity for M6P under acidic pH conditions.
