K+ channels are an important target for drugs to treat a variety of disorders, including high blood pressure, diabetes, asthma, multiple scleroisis, and others. In addition, the genetic disease, Periodic Ataxia and certain forms of Long Q-T syndrome, have been linked to specific point mutations in K+ channel proteins. Despite the importance these channels have in maintaining normal physiology, and their net therapeutic importance, relatively little is known about how K+ channel assembly by the N-terminal T1 domain. The experiments the investigator will perform in this proposal are motivated by the progress he has achieved in understanding the assembly mechanisms of voltage gated K channels from the original proposal. In this new project, the investigator will determine the crystallographic structure of the T1 domain protein in collaboration with Dr. Senyon Choe, confirm the structural model in isolated T1 domain proteins and full length channels, identify critical residues and interactions for K channel assembly, and characterize the alterations in channel assembly identity produced by T1 domain mutations. The long term goal is to understand how information needed to encode the precise electrophysiological properties of the nervous system are encoded by structural differences in the T1 domain of K channel subunit proteins. This goal will be addressed by experiments that will satisfy the following Specific Aims: 1) Determination of the structure of the tetrameric T1 domain and identification of functionally significant regions of the T1 domain protein; 2) analysis of residues that are functionally important for T1 domain tetramerization and confirmation of the T1 domain structure; and 3) analysis of the T1 domain in the full length channel subunit protein and its role in controlling channel protein assembly. The general approach in these studies is to integrate structural information with functional information on wild type and mutant T1 domain assembly in isolated protein preparations, and for full length subunit protein assembly, and intact cells. By careful characterization of the changes in assembly properties caused by these individual mutations, the investigators can dissect the functional roles for specific residues and residue interactions in producing the ordered assembly of K channel subunit protein in the nervous system.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Physiology Study Section (PHY)
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Talley, Edmund M
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Baylor College of Medicine
Schools of Medicine
United States
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Kunjilwar, Kumud; Qian, Yan; Pfaffinger, Paul J (2013) Functional stoichiometry underlying KChIP regulation of Kv4.2 functional expression. J Neurochem 126:462-72
Prince-Carter, Alison; Pfaffinger, Paul J (2009) Multiple intermediate states precede pore block during N-type inactivation of a voltage-gated potassium channel. J Gen Physiol 134:15-34
Lauver, Aaron; Yuan, Li-Lian; Jeromin, Andreas et al. (2006) Manipulating Kv4.2 identifies a specific component of hippocampal pyramidal neuron A-current that depends upon Kv4.2 expression. J Neurochem 99:1207-23
Wang, Guangyu; Shahidullah, Mohammad; Rocha, Carmen A et al. (2005) Functionally active t1-t1 interfaces revealed by the accessibility of intracellular thiolate groups in kv4 channels. J Gen Physiol 126:55-69
Jerng, Henry H; Kunjilwar, Kumud; Pfaffinger, Paul J (2005) Multiprotein assembly of Kv4.2, KChIP3 and DPP10 produces ternary channel complexes with ISA-like properties. J Physiol 568:767-88
Jerng, Henry H; Qian, Yan; Pfaffinger, Paul J (2004) Modulation of Kv4.2 channel expression and gating by dipeptidyl peptidase 10 (DPP10). Biophys J 87:2380-96
Jerng, Henry H; Pfaffinger, Paul J; Covarrubias, Manuel (2004) Molecular physiology and modulation of somatodendritic A-type potassium channels. Mol Cell Neurosci 27:343-69
Zhou, Wei; Qian, Yan; Kunjilwar, Kumud et al. (2004) Structural insights into the functional interaction of KChIP1 with Shal-type K(+) channels. Neuron 41:573-86
Kunjilwar, Kumud; Strang, Candace; DeRubeis, David et al. (2004) KChIP3 rescues the functional expression of Shal channel tetramerization mutants. J Biol Chem 279:54542-51
Nanao, Max H; Zhou, Wei; Pfaffinger, Paul J et al. (2003) Determining the basis of channel-tetramerization specificity by x-ray crystallography and a sequence-comparison algorithm: Family Values (FamVal). Proc Natl Acad Sci U S A 100:8670-5

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