exam_1_summer_2009_key

exam_1_summer_2009_key - BIS 104 (Waddell) Summer 2009...

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BIS 104 (Waddell) Name:________________________ Summer 2009 Last, First Version A ID #:_________________________ BIS-104 MIDTERM I This exam has a total of 150 points. READ EACH QUESTION CAREFULLY BEFORE YOU ANSWER. SHOW ALL YOUR WORK TO GET FULL CREDIT. Please sign your name below and on the score sheet. This exam has 5 questions and is 8 pages including the cover page and score sheet. HONOR CODE: My signature below affirms that I wrote this exam in the spirit of the honor system of the University of California, Davis. I neither received nor furnished any help during the exam, nor did I use any unauthorized references. Signature:____________________________ Authorization for Public Distribution of Graded Examination I, _____________________________, ID#_________________________, authorize this exam to be placed in a holding bin following grading. The bins will be labeled BIS 104/Waddell, on the first floor of Briggs Hall.
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BIS 104 Name:________________________ Summer Session II 2009 Last, First Midterm I Question Points 1 ________ 2 ________ 3 ________ 4 ________ 5 ________ Total ________
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BIS 104 Name:________________________ Summer Session II 2009 Last, First 1. You are interested in the function of a protein called Mtm1 that has a Pleckstrin Homology Domain (PH) domain, a SH3 domain and a SH2 domain, also called a Phosphotyrosine Binding (PTB) domain. Mtm1functions downstream of the insulin receptor, a Receptor Tyrosine Kinase (RTK), by binding to the receptor in an insulin-dependent fashion via its SH2 domain. You create mutant forms of Mtm1 that delete the various protein domains. You find that these mutations do not seem to affect the protein level or folding of Mtm1. You examine the cellular localization of Mtm1and the Mtm1 mutants and the results are summarized in Table 1. ( Note: The number of plus signs indicates the relative level of Mtm1 or mutant Mtm1 found at that cellular location.) Table 1 In Table 1, the letter D indicates that the following protein domain is deleted. For example, mtmD PH indicates an Mtm1 protein that lacks the PH domain; mtmD PHDSH3 indicates an mtm1 protein that lacks both the PH domain and the SH3 domain. A. Explain the function of each of these domains and given the data above, explain the role of the PH, SH2, and SH3 domains in localizing the Mtm1 protein. In other words, explain how this protein most likely associates with its binding partners at the plasma membrane and the order in which this association most likely occurs. (15 Points) Both the PH domain and the SH2 (PTB) domain are important for the localization of the protein to the plasma membrane, with the SH2 domain having a slightly greater role than the PH domain. Mtm1 localizes to the plasma membrane when cells are exposed to insulin. SH2 domains bind to activated insulin receptors by binding to phosphotyrosines. PH domains can bind to PIP3 on the inner surface of the plasma membrane when these lipids are produced by PI 3-kinase in response to insulin signaling. The SH2 domain and the PH domains work in concert
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This note was uploaded on 03/20/2010 for the course BIS BIS 104 taught by Professor Privalsky during the Spring '09 term at UC Davis.

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exam_1_summer_2009_key - BIS 104 (Waddell) Summer 2009...

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