Humans who have mutations in the presenilin genes are at a higher risk for developing early-onset Alzheimer's disease. The human presenilin proteins that are made from these genes are responsible for altering other proteins by cleaving (cutting) them at specific positions. Presenilin proteins that are highly similar to the human ones have been identified in C. elegans, a microscopic nematode worm. These nematodes do not get Alzheimer's disease, as they do not have a brain. What would you expect the function of nematode presenilins to be?
A) They are responsible for the development of the central nervous system.
B) They are responsible for altering other proteins by cleaving them.
C) They are responsible for transporting proteins to a new location within cells.
D) They are responsible for the synthesis of new proteins.

Question

Quizplus · Accepted Answer

Since the human presenilin proteins are responsible for altering other proteins by cleaving them, we can expect the nematode presenilins to have a similar function to cleave other proteins at specific positions. This function may be important in cellular processes such as protein degradation and signaling.

Humans Who Have Mutations in the Presenilin Genes Are at a Higher