You have isolated two mutants of a normally pear-shaped microorganism that have lost their distinctive shape and are now round. One of the mutants has a defect in a protein that you call A and the other has a defect in a protein that you call B. First, you grind up each type of mutant cell and normal cells separately and separate the plasma membranes from the cytoplasm, forming the first cell extract. Then you set aside a portion of each fraction for later testing. Next, you wash the remaining portion of the membrane fractions with a low concentration of urea (which will unfold proteins and disrupt their ability to interact with other proteins) and centrifuge the mixture. The membranes and their constituent proteins form a pellet, and the proteins liberated from the membranes by the urea wash remain in the supernatant. When you check each of the fractions for the presence of A or B, you obtain the results given below.

First cell extract After urea wash and centrifugation
Membrane Cytosol Membrane Supernatant
Normal cells no A or B A and B A B
Mutant A A B A no A or B
Mutant B A B A no A or B

Which of the following statements are consistent with your results (more than one answer may apply)?

A) Proteins A and B are both integral membrane proteins.
B) Protein B is an integral membrane protein that interacts with A, a peripheral membrane protein that is part of the cell cortex.
C) Protein A is an integral membrane protein that interacts with B, a peripheral membrane protein that is part of the cell cortex.
D) The mutation in A affects its ability to interact with B.