Question 6 The bos/seven receptor is required for differentiation of a particular cell, called R7. It is a receptor tyrosine kinase with the structure below. As a monomer, the protein is inactive Binding of ligand causes the receptor to dimerize, causing phosphorylation of the intracellular domain, activating the protein. During processing of the protein, the extracellular domain is cleaved and a disulfide bridge forms between two cysteines, tethering the ligand-binding domain to the rest of the protein ligand-binding domain extracellular S-s S-s membraneITITIIIITTTIIiIli intracellular NACTIVE ACTIVE i) How would receptor activity be affected by changing one of the two cysteines shown above to an alanine? explain ii) What effect would this mutation have on the differentiation of r7? b) Name three amino acids that would be likely to be found in the transmembrane domain. What property do those amino acids have in common, and why do they cause the transmembrane domain to stay in the membrane? d) Draw a schematic of the receptor tyrosine kinase(discussed above) prior to any cleavage or modification using the template below. Include the domains of this protein that are required for targeting to and insertion in the plasma membrane. Also label the intracellular and extracellular domains C e)Activation of the above receptor causes Ras to exchange GDP for GTP, thereby activating it This activated Ras can activate a signal transduction cascade, which ultimately results in the Spring 2004 Final exam practiceSpring 2004 Final Exam Practice 9 Question 6 The bos/seven receptor is required for differentiation of a particular cell, called R7. It is a receptor tyrosine kinase with the structure below. As a monomer, the protein is inactive. Binding of ligand causes the receptor to dimerize, causing phosphorylation of the intracellular domain, activating the protein. During processing of the protein, the extracellular domain is cleaved and a disulfide bridge forms between two cysteines, tethering the ligand-binding domain to the rest of the protein. -S-S￾ligand-binding domain intracellular extracellular membrane -S-S- -S-S￾ligand INACTIVE ACTIVE P P a) i) How would receptor activity be affected by changing one of the two cysteines shown above to an alanine? Explain. ii) What effect would this mutation have on the differentiation of R7? b) Name three amino acids that would be likely to be found in the transmembrane domain. What property do those amino acids have in common, and why do they cause the transmembrane domain to stay in the membrane? d) Draw a schematic of the receptor tyrosine kinase (discussed above) prior to any cleavage or modification using the template below. Include the domains of this protein that are required for targeting to and insertion in the plasma membrane. Also label the intracellular and extracellular domains. N C e) Activation of the above receptor causes Ras to exchange GDP for GTP, thereby activating it. This activated Ras can activate a signal transduction cascade, which ultimately results in the