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Unformatted text preview: ed motif in the cytoplasmic portion of the protein that
contains Ser-Ser-Thr. You want to show that if you prevent the constitutive b-arrestin mediated
endocytosis of the mutant B version of the RKR receptor that it will then be capable of signaling
Your advisor suggests that you mutate all three residues to alanine in the mutant receptor? Why
does he choose these three residues? Why does he suggest mutating them to alanine?
After extended exposure to ligand, GPCRs become phosphorylated and then b-arrestin can
bind to the phosphorylated residues and this results in endocytosis of the receptor and
termination of signaling. Serine, threonine and tyrosine are all residues that can be
phosphorylated and hence if they are converted to another residue then you won’t get
internalization of the receptor.
He chose alanine because it is small and so probably won’t affect the secondary structure of
the protein and also it is used in mutagenesis studies because it allows you to determine the
functional importance of the side chain of an amino acid – which is where phosphorylation
occurs on serine and threonine....
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This note was uploaded on 01/23/2012 for the course LSM lsm1301 taught by Professor Seow during the Spring '11 term at National University of Singapore.
- Spring '11