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Chen JJ, Kaufmann WA, Chen C, Arai I, Kim O, Shigemoto R, Jonas P. Developmental transformation of Ca 2+ channel-vesicle nanotopography at a central GABAergic synapse. Neuron 2024; 112:755-771.e9. [PMID: 38215739 DOI: 10.1016/j.neuron.2023.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 07/12/2023] [Accepted: 12/05/2023] [Indexed: 01/14/2024]
Abstract
The coupling between Ca2+ channels and release sensors is a key factor defining the signaling properties of a synapse. However, the coupling nanotopography at many synapses remains unknown, and it is unclear how it changes during development. To address these questions, we examined coupling at the cerebellar inhibitory basket cell (BC)-Purkinje cell (PC) synapse. Biophysical analysis of transmission by paired recording and intracellular pipette perfusion revealed that the effects of exogenous Ca2+ chelators decreased during development, despite constant reliance of release on P/Q-type Ca2+ channels. Structural analysis by freeze-fracture replica labeling (FRL) and transmission electron microscopy (EM) indicated that presynaptic P/Q-type Ca2+ channels formed nanoclusters throughout development, whereas docked vesicles were only clustered at later developmental stages. Modeling suggested a developmental transformation from a more random to a more clustered coupling nanotopography. Thus, presynaptic signaling developmentally approaches a point-to-point configuration, optimizing speed, reliability, and energy efficiency of synaptic transmission.
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Affiliation(s)
- Jing-Jing Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Chong Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Itaru Arai
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Olena Kim
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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2
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Atlas D. Revisiting the molecular basis of synaptic transmission. Prog Neurobiol 2022; 216:102312. [PMID: 35760141 DOI: 10.1016/j.pneurobio.2022.102312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/12/2022] [Accepted: 06/20/2022] [Indexed: 10/17/2022]
Abstract
Measurements of the time elapsed during synaptic transmission has shown that synaptic vesicle (SV) fusion lags behind Ca2+-influx by approximately 60 microseconds (µsec). The conventional model cannot explain this extreme rapidity of the release event. Synaptic transmission occurs at the active zone (AZ), which comprises of two pools of SV, non-releasable "tethered" vesicles, and a readily-releasable pool of channel-associated Ca2+-primed vesicles, "RRP". A recent TIRF study at cerebellar-mossy fiber-terminal, showed that subsequent to an action potential, newly "tethered" vesicles, became fusion-competent in a Ca2+-dependent manner, 300-400 milliseconds after tethering, but were not fused. This time resolution may correspond to priming of tethered vesicles through Ca2+-binding to Syt1/Munc13-1/complexin. It confirms that Ca2+-priming and Ca2+-influx-independent fusion, are two distinct events. Notably, we have established that Ca2+ channel signals evoked-release in an ion flux-independent manner, demonstrated by Ca2+-impermeable channel, or a Ca2+ channel in which Ca2+ is replaced by impermeable La3+. Thus, conformational changes in a channel coupled to RRP appear to directly activate the release machinery and account for a µsec Ca2+-influx-independent vesicle fusion. Rapid vesicle fusion driven by non-ionotropic channel signaling strengthens a conformational-coupling mechanism of synaptic transmission, and contributes to better understanding of neuronal communication vital for brain function.
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Affiliation(s)
- Daphne Atlas
- Dept. of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904 Israel.
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3
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Hwang JY, Mannowetz N, Zhang Y, Everley RA, Gygi SP, Bewersdorf J, Lishko PV, Chung JJ. Dual Sensing of Physiologic pH and Calcium by EFCAB9 Regulates Sperm Motility. Cell 2019; 177:1480-1494.e19. [PMID: 31056283 DOI: 10.1016/j.cell.2019.03.047] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 02/08/2019] [Accepted: 03/25/2019] [Indexed: 11/24/2022]
Abstract
Varying pH of luminal fluid along the female reproductive tract is a physiological cue that modulates sperm motility. CatSper is a sperm-specific, pH-sensitive calcium channel essential for hyperactivated motility and male fertility. Multi-subunit CatSper channel complexes organize linear Ca2+ signaling nanodomains along the sperm tail. Here, we identify EF-hand calcium-binding domain-containing protein 9 (EFCAB9) as a bifunctional, cytoplasmic machine modulating the channel activity and the domain organization of CatSper. Knockout mice studies demonstrate that EFCAB9, in complex with the CatSper subunit, CATSPERζ, is essential for pH-dependent and Ca2+-sensitive activation of the CatSper channel. In the absence of EFCAB9, sperm motility and fertility is compromised, and the linear arrangement of the Ca2+ signaling domains is disrupted. EFCAB9 interacts directly with CATSPERζ in a Ca2+-dependent manner and dissociates at elevated pH. These observations suggest that EFCAB9 is a long-sought, intracellular, pH-dependent Ca2+ sensor that triggers changes in sperm motility.
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Chen C, Satterfield R, Young SM, Jonas P. Triple Function of Synaptotagmin 7 Ensures Efficiency of High-Frequency Transmission at Central GABAergic Synapses. Cell Rep 2018; 21:2082-2089. [PMID: 29166601 PMCID: PMC5863544 DOI: 10.1016/j.celrep.2017.10.122] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/06/2017] [Accepted: 10/29/2017] [Indexed: 12/21/2022] Open
Abstract
Synaptotagmin 7 (Syt7) is thought to be a Ca2+ sensor that mediates asynchronous transmitter release and facilitation at synapses. However, Syt7 is strongly expressed in fast-spiking, parvalbumin-expressing GABAergic interneurons, and the output synapses of these neurons produce only minimal asynchronous release and show depression rather than facilitation. To resolve this apparent contradiction, we examined the effects of genetic elimination of Syt7 on synaptic transmission at the GABAergic basket cell (BC)-Purkinje cell (PC) synapse in cerebellum. Our results indicate that at the BC-PC synapse, Syt7 contributes to asynchronous release, pool replenishment, and facilitation. In combination, these three effects ensure efficient transmitter release during high-frequency activity and guarantee frequency independence of inhibition. Our results identify a distinct function of Syt7: ensuring the efficiency of high-frequency inhibitory synaptic transmission.
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Affiliation(s)
- Chong Chen
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria
| | - Rachel Satterfield
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA
| | - Samuel M Young
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA; Department of Anatomy and Cell Biology, Department of Otolaryngology, Iowa Neuroscience Institute, Aging Mind Brain Initiative, University of Iowa, Iowa City, IA 52242, USA
| | - Peter Jonas
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria.
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5
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Yang T, Hu N, Pangršič T, Green S, Hansen M, Lee A. Functions of CaBP1 and CaBP2 in the peripheral auditory system. Hear Res 2018; 364:48-58. [PMID: 29661613 DOI: 10.1016/j.heares.2018.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/13/2018] [Accepted: 04/02/2018] [Indexed: 12/29/2022]
Abstract
CaBPs are a family of Ca2+ binding proteins related to calmodulin. Two CaBP family members, CaBP1 and CaBP2, are highly expressed in the cochlea. Here, we investigated the significance of CaBP1 and CaBP2 for hearing in mice lacking expression of these proteins (CaBP1 KO and CaBP2 KO) using auditory brain responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). In CaBP1 KO mice, ABR wave I was larger in amplitude, and shorter in latency and faster in decay, suggestive of enhanced synchrony of auditory nerve fibers. This interpretation was supported by the greater excitability of CaBP1 KO than WT neurons in whole-cell patch clamp recordings of spiral ganglion neurons in culture, and normal presynaptic function of CaBP1 KO IHCs. DPOAEs and ABR thresholds were normal in 4-week old CaBP1 KO mice, but elevated ABR thresholds became evident at 32 kHz at 9 weeks, and at 8 and 16 kHz by 6 months of age. In contrast, CaBP2 KO mice exhibited significant ABR threshold elevations at 4 weeks of age that became more severe in the mid-frequency range by 9 weeks. Though normal at 4 weeks, DPOAEs in CaBP2 KO mice were significantly reduced in the mid-frequency range by 9 weeks. Our results reveal requirements for CaBP1 and CaBP2 in the peripheral auditory system and highlight the diverse modes by which CaBPs influence sensory processing.
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Affiliation(s)
- Tian Yang
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Ning Hu
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Tina Pangršič
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Steven Green
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Marlan Hansen
- Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA.
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6
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Chen C, Arai I, Satterfield R, Young SM, Jonas P. Synaptotagmin 2 Is the Fast Ca 2+ Sensor at a Central Inhibitory Synapse. Cell Rep 2017; 18:723-736. [PMID: 28099850 PMCID: PMC5276807 DOI: 10.1016/j.celrep.2016.12.067] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/18/2016] [Accepted: 12/20/2016] [Indexed: 11/24/2022] Open
Abstract
GABAergic synapses in brain circuits generate inhibitory output signals with submillisecond latency and temporal precision. Whether the molecular identity of the release sensor contributes to these signaling properties remains unclear. Here, we examined the Ca2+ sensor of exocytosis at GABAergic basket cell (BC) to Purkinje cell (PC) synapses in cerebellum. Immunolabeling suggested that BC terminals selectively expressed synaptotagmin 2 (Syt2), whereas synaptotagmin 1 (Syt1) was enriched in excitatory terminals. Genetic elimination of Syt2 reduced action potential-evoked release to ∼10%, identifying Syt2 as the major Ca2+ sensor at BC-PC synapses. Differential adenovirus-mediated rescue revealed that Syt2 triggered release with shorter latency and higher temporal precision and mediated faster vesicle pool replenishment than Syt1. Furthermore, deletion of Syt2 severely reduced and delayed disynaptic inhibition following parallel fiber stimulation. Thus, the selective use of Syt2 as release sensor at BC-PC synapses ensures fast and efficient feedforward inhibition in cerebellar microcircuits. Syt2 is the Ca2+ sensor of fast transmitter release at a cerebellar GABAergic synapse Syt2 triggers transmitter release with faster time course than Syt1 Syt2 ensures faster replenishment of the readily releasable pool than Syt1 Syt2 is essential for fast feedforward inhibition in cerebellar microcircuits
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Affiliation(s)
- Chong Chen
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Itaru Arai
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Rachel Satterfield
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA
| | - Samuel M Young
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA
| | - Peter Jonas
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
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7
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La Verde V, Trande M, D'Onofrio M, Dominici P, Astegno A. Binding of calcium and target peptide to calmodulin-like protein CML19, the centrin 2 of Arabidopsis thaliana. Int J Biol Macromol 2017; 108:1289-1299. [PMID: 29129631 DOI: 10.1016/j.ijbiomac.2017.11.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 01/03/2023]
Abstract
Calmodulin-like protein 19 (CML19) is an Arabidopsis centrin that modulates nucleotide excision repair (NER) by binding to RAD4 protein, the Arabidopsis homolog of human Xeroderma pigmentosum complementation group C protein. Although the necessity of CML19 as a part of the RAD4 plant recognition complex for functional NER is known at a cellular level, little is known at a molecular level. Herein, we used a combination of biophysical and biochemical approaches to investigate the structural and ion and target-peptide binding properties of CML19. We found that CML19 possesses four Ca2+-specific binding sites, two of high affinity in the N-terminal domain and two of low affinity in the C-terminal domain. Binding of Ca2+ to CML19 increases its alpha-helix content, stabilizes the tertiary structure, and triggers a conformational change, resulting in the exposure of a hydrophobic patch instrumental for target protein recognition. Using bioinformatics tools we identified a CML19-binding site at the C-terminus of RAD4, and through in vitro binding experiments we analyzed the interaction between a 17-mer peptide representing this site and CML19. We found that the peptide shows a high affinity for CML19 in the presence of Ca2+ (stoichiometry 1:1) and the interaction primarily involves the C-terminal half of CML19.
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Affiliation(s)
- Valentina La Verde
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Matteo Trande
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Mariapina D'Onofrio
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy.
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Nakamura TY, Nakao S, Wakabayashi S. Neuronal Ca 2+ sensor-1 contributes to stress tolerance in cardiomyocytes via activation of mitochondrial detoxification pathways. J Mol Cell Cardiol 2016; 99:23-34. [PMID: 27555477 DOI: 10.1016/j.yjmcc.2016.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/13/2016] [Accepted: 08/18/2016] [Indexed: 01/28/2023]
Abstract
Identification of the molecules involved in cell death/survival pathways is important for understanding the mechanisms of cell loss in cardiac disease, and thus is clinically relevant. Ca2+-dependent signals are often involved in these pathways. Here, we found that neuronal Ca2+-sensor-1 (NCS-1), a Ca2+-binding protein, has an important role in cardiac survival during stress. Cardiomyocytes derived from NCS-1-deficient (Ncs1-/-) mice were more susceptible to oxidative and metabolic stress than wild-type (WT) myocytes. Cellular ATP levels and mitochondrial respiration rates, as well as the levels of mitochondrial marker proteins, were lower in Ncs1-/- myocytes. Although oxidative stress elevated mitochondrial proton leak, which exerts a protective effect by inhibiting the production of reactive oxygen species in WT myocytes, this response was considerably diminished in Ncs1-/- cardiomyocytes, and this would be a major reason for cell death. Consistently, H2O2-induced loss of mitochondrial membrane potential, a critical early event in cell death, was accelerated in Ncs1-/- myocytes. Furthermore, NCS-1 was upregulated in hearts subjected to ischemia-reperfusion, and ischemia-reperfusion injury was more severe in Ncs1-/- hearts. Activation of stress-induced Ca2+-dependent survival pathways, such as Akt and PGC-1α (which promotes mitochondrial biogenesis and function), was diminished in Ncs1-/- hearts. Overall, these data demonstrate that NCS-1 contributes to stress tolerance in cardiomyocytes at least in part by activating certain Ca2+-dependent survival pathways that promote mitochondrial biosynthesis/function and detoxification pathways.
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Affiliation(s)
- Tomoe Y Nakamura
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan.
| | - Shu Nakao
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
| | - Shigeo Wakabayashi
- Department of Molecular Physiology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan; Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
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Kim KY, Scholl ES, Liu X, Shepherd A, Haeseleer F, Lee A. Localization and expression of CaBP1/caldendrin in the mouse brain. Neuroscience 2014; 268:33-47. [PMID: 24631676 DOI: 10.1016/j.neuroscience.2014.02.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/26/2014] [Accepted: 02/27/2014] [Indexed: 12/31/2022]
Abstract
Ca(2+) binding protein 1 (CaBP1) and caldendrin are alternatively spliced variants of a subfamily of CaBPs with high homology to calmodulin. Although CaBP1 and caldendrin regulate effectors including plasma membrane and intracellular Ca(2+) channels in heterologous expression systems, little is known about their functions in vivo. Therefore, we generated mice deficient in CaBP1/caldendrin expression (C-KO) and analyzed the expression and cellular localization of CaBP1 and caldendrin in the mouse brain. Immunoperoxidase labeling with antibodies recognizing both CaBP1 and caldendrin was absent in the brain of C-KO mice, but was intense in multiple brain regions of wild-type mice. By Western blot, the antibodies detected two proteins that were absent in the C-KO mouse and consistent in size with caldendrin variants originating from alternative translation initiation sites. By quantitative PCR, caldendrin transcript levels were far greater than those for CaBP1, particularly in the cerebral cortex and hippocampus. In the frontal cortex but not in the hippocampus, caldendrin expression increased steadily from birth. By double-label immunofluorescence, CaBP1/caldendrin was localized in principal neurons and parvalbumin-positive interneurons. In the cerebellum, CaBP1/caldendrin antibodies labeled interneurons in the molecular layer and in basket cell terminals surrounding the soma and axon initial segment of Purkinje neurons, but immunolabeling was absent in Purkinje neurons. We conclude that CaBP1/caldendrin is localized both pre- and postsynaptically where it may regulate Ca(2+) signaling and excitability in select groups of excitatory and inhibitory neurons.
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Affiliation(s)
- K Y Kim
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - E S Scholl
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - X Liu
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - A Shepherd
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - F Haeseleer
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - A Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Iowa City, IA 52242, USA.
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