You know that the amino acid sequence of a protein contains targeting information that determines where...

 

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You know that the amino acid sequence of a protein contains "targeting" information that determines where the protein will be transported after synthesis. You are analyzing a set of cultured cell lines that have highly deleterious mutations in genes that encode proteins involved in organelle traffic in the cell. The cellular phenotype of each mutation is described in the table below. Match each phenotype with the change in targeting information that is most likely to have produced it. Possible changes in proteins: (A) Change in a single amino acid critical for the addition to this protein of a sugar chain ending in mannose-6-phosphate. (B) Deletion of this protein's C-terminal KDEL sequence. (C) Deletion of this protein's C-terminal 4-6 amino acid "hook" motif. (D) Change in the mannose-6-phosphate receptor so that it cannot recognize its ligand. (E) Deletion of an N-terminal hydrophobic signal sequence from this protein. (F) Deletion of the LDL receptor. (G) Addition of an N-terminal hydrophobic signal sequence to this protein. Change most likely responsible (A - H) Complete cellular phenotype Secretion of actin, normally a cytoplasmic protein Failure of one protease, cathepsin B, to reach the lysosome Failure of signal peptidase to be inserted into the ER Failure of any degradative enzymes to reach the lysosome Failure of a receptor, the transferrin receptor, to be internalized by endocytosis Secretion of signal peptidase, which normally resides in the ER Submit Answer Tries 0/3 This discussion is closed. You know that the amino acid sequence of a protein contains "targeting" information that determines where the protein will be transported after synthesis. You are analyzing a set of cultured cell lines that have highly deleterious mutations in genes that encode proteins involved in organelle traffic in the cell. The cellular phenotype of each mutation is described in the table below. Match each phenotype with the change in targeting information that is most likely to have produced it. Possible changes in proteins: (A) Change in a single amino acid critical for the addition to this protein of a sugar chain ending in mannose-6-phosphate. (B) Deletion of this protein's C-terminal KDEL sequence. (C) Deletion of this protein's C-terminal 4-6 amino acid "hook" motif. (D) Change in the mannose-6-phosphate receptor so that it cannot recognize its ligand. (E) Deletion of an N-terminal hydrophobic signal sequence from this protein. (F) Deletion of the LDL receptor. (G) Addition of an N-terminal hydrophobic signal sequence to this protein. Change most likely responsible (A - H) Complete cellular phenotype Secretion of actin, normally a cytoplasmic protein Failure of one protease, cathepsin B, to reach the lysosome Failure of signal peptidase to be inserted into the ER Failure of any degradative enzymes to reach the lysosome Failure of a receptor, the transferrin receptor, to be internalized by endocytosis Secretion of signal peptidase, which normally resides in the ER Submit Answer Tries 0/3 This discussion is closed.

Answer rating: 100% (QA)

Required correct option is matched 1Secretion of BiP a protein normally found in ER lumen 2 Deletion ... View the full answer