Voltage dependent Ca2+ channels are transmembrane proteins, which allow Ca2+ entry upon activation. In addition to their electrogenic role, Ca2+ channels provide a pivotal link between membrane depolarization and a wide range of cellular functions. Ca2+ action is often local and close to its source of entrance. Ca2+ action is also very specific. Ca2+ influx through different types of Ca2+ channels can activate distinct cellular signaling cascades. For instance, compared to L-type Ca2+ channels, Ca2+ influx through NMDA receptors activates a distinct signaling pathway for regulation of gene expression. With its abundant and varied intracellular targets, how is Ca2+ able to achieve specificity and activate only a subset those targets in neurons? The long-term goal is to understand the role and molecular mechanisms of Ca2+ channels in neuronal signaling. Specifically, in this proposal, we will test the hypothesis that specific interactions exist between Ca2+ channels and certain other intracellular proteins. Such interactions are of functional significance.
Specific aims i nclude isolation and characterization of proteins, which interact with Ca2+ channels. Using yeast two-hybrid system, we have screened a brain cDNA library with the C-termini of three different Ca2+ channel alpha1-subunits as baits. 177 clones have been sequenced. Three clones have been selected for functional studies. They include tctex-1, a light chain of the dynein complex; clones L157 and N397, two distinct forms of PKC binding proteins. Experiments are in progress to address the functional significance of the interactions between Ca2+ channels and those clones in the following aspects: (1) differential distribution of different types of Ca2+ channels in neurons (tctex-1); and (2) modulation of channel activities by PKC and/or initiation of the PKC signaling cascade (L157 & N397). Preliminary data indicate that the interaction between Ca2+ channels and these clones we selected indeed bears the functional significance as we had hypothesized.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS039355-01A2
Application #
6334135
Study Section
Special Emphasis Panel (ZRG1-MDCN-4 (01))
Program Officer
Talley, Edmund M
Project Start
2001-05-01
Project End
2005-04-30
Budget Start
2001-05-01
Budget End
2002-04-30
Support Year
1
Fiscal Year
2001
Total Cost
$367,519
Indirect Cost
Name
University of Pennsylvania
Department
Pharmacology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Zhang, Miao; Meng, Xuan-Yu; Cui, Meng et al. (2014) Selective phosphorylation modulates the PIP2 sensitivity of the CaM-SK channel complex. Nat Chem Biol 10:753-9
Zhang, Miao; Pascal, John M; Zhang, Ji-Fang (2013) Unstructured to structured transition of an intrinsically disordered protein peptide in coupling Ca²?-sensing and SK channel activation. Proc Natl Acad Sci U S A 110:4828-33
Zhang, Miao; Abrams, Cameron; Wang, Liping et al. (2012) Structural basis for calmodulin as a dynamic calcium sensor. Structure 20:911-23
Zhang, Jifeng; Fan, Jinjin; Tian, Qi et al. (2012) Characterization of two distinct modes of endophilin in clathrin-mediated endocytosis. Cell Signal 24:2043-50
Zhang, Miao; Pascal, John M; Schumann, Marcel et al. (2012) Identification of the functional binding pocket for compounds targeting small-conductance Ca²?-activated potassium channels. Nat Commun 3:1021
Chen, Yuan; Lai, Meizan; Maeno-Hikichi, Yuka et al. (2006) Essential role of the LIM domain in the formation of the PKCepsilon-ENH-N-type Ca2+ channel complex. Cell Signal 18:215-24
Li, Dongjun; Wang, Fushun; Lai, Meizan et al. (2005) A protein phosphatase 2calpha-Ca2+ channel complex for dephosphorylation of neuronal Ca2+ channels phosphorylated by protein kinase C. J Neurosci 25:1914-23
Maeno-Hikichi, Yuka; Chang, Shaohua; Matsumura, Kiyoyuki et al. (2003) A PKC epsilon-ENH-channel complex specifically modulates N-type Ca2+ channels. Nat Neurosci 6:468-75
Chen, Yuan; Deng, Lunbin; Maeno-Hikichi, Yuka et al. (2003) Formation of an endophilin-Ca2+ channel complex is critical for clathrin-mediated synaptic vesicle endocytosis. Cell 115:37-48