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Manuel Criado - One of the best experts on this subject based on the ideXlab platform.

  • Subcellular compartmentalization of a Potassium Channel (Kv1.4): preferential distribution in dendrites and dendritic spines of neurons in the dorsal cochlear nucleus.
    The European journal of neuroscience, 2000
    Co-Authors: José M. Juiz, Rafael Luján, Eduardo Domínguez Del Toro, V. Fuentes, Juan J. Ballesta, Manuel Criado
    Abstract:

    Voltage-dependent ion Channels have specific patterns of distribution along the neuronal plasma membrane of dendrites, cell bodies and axons, which need to be unravelled in order to understand their contribution to neuronal excitability and firing patterns. We have investigated the subcellular compartmentalization of Kv1.4, a transient, fast-inactivating Potassium Channel, in fusiform cells and related interneurons of the rat dorsal cochlear nucleus. A polyclonal antibody which binds to a region near the N-terminus domain of a Kv1.4 Channel was raised in rabbits. Using a high-resolution combination of immunocytochemical methods, Kv1.4 was localized mainly in the apical dendritic trunks and cell bodies of fusiform cells, as well as in dendrites and cell bodies of interneurons of the dorsal cochlear nucleus, likely cartwheel cells. Quantitative immunogold immunocytochemistry revealed a pronounced distal to proximal gradient in the dendrosomatic distribution of Kv1. 4. In plasma membrane localizations, Kv1.4 was preferentially present in dendritic spines, either in the spine neck or in perisynaptic locations, always away from the postsynaptic density. These findings indicate that Kv1.4 is largely distributed in dendritic compartments of fusiform and cartwheel cells of the dorsal cochlear nucleus. Its preferential localization in dendritic spines, where granule cell axons make powerful excitatory synapses, suggests a role for this voltage-dependent ion Channel in the regulation of dendritic excitability and excitatory inputs.

Morgan Sheng - One of the best experts on this subject based on the ideXlab platform.

  • requirement of n terminal cysteines of psd 95 for psd 95 multimerization and ternary complex formation but not for binding to Potassium Channel Kv1.4
    Journal of Biological Chemistry, 1999
    Co-Authors: Yiping Hsueh, Morgan Sheng
    Abstract:

    The PSD-95 family of PSD-95/Discs large/ZO-1 (PDZ) domain-containing proteins plays a role in the clustering and localization of specific ion Channels and receptors at synapses. Previous studies have shown that PSD-95 forms multimers through an N-terminal region (termed the N-segment) and that the multimerization of PSD-95 is critical for its ability to cluster Shaker-type Potassium Channel Kv1.4 in heterologous cells. We show here that the PSD-95 N-segment functions as a multimerization domain only when located at the N-terminal end of a heterologous protein. A pair of N-terminal cysteines, Cys3 and Cys5, is essential for the ability of PSD-95 to self-associate and to form cell surface clusters with Kv1.4. However, PSD-95 mutants lacking these cysteine residues retain their ability to associate with membranes and to bind to Kv1.4. Unlike wild type PSD-95, the cysteine mutant of PSD-95 cannot form a ternary complex with Kv1.4 and the cell adhesion molecule Fasciclin II. These results suggest that the N-terminal cysteines are essential for PSD-95 multimerization and that multimerization is required for simultaneous binding of multiple membrane protein ligands by PSD-95.

José M. Juiz - One of the best experts on this subject based on the ideXlab platform.

  • Subcellular compartmentalization of a Potassium Channel (Kv1.4): preferential distribution in dendrites and dendritic spines of neurons in the dorsal cochlear nucleus.
    The European journal of neuroscience, 2000
    Co-Authors: José M. Juiz, Rafael Luján, Eduardo Domínguez Del Toro, V. Fuentes, Juan J. Ballesta, Manuel Criado
    Abstract:

    Voltage-dependent ion Channels have specific patterns of distribution along the neuronal plasma membrane of dendrites, cell bodies and axons, which need to be unravelled in order to understand their contribution to neuronal excitability and firing patterns. We have investigated the subcellular compartmentalization of Kv1.4, a transient, fast-inactivating Potassium Channel, in fusiform cells and related interneurons of the rat dorsal cochlear nucleus. A polyclonal antibody which binds to a region near the N-terminus domain of a Kv1.4 Channel was raised in rabbits. Using a high-resolution combination of immunocytochemical methods, Kv1.4 was localized mainly in the apical dendritic trunks and cell bodies of fusiform cells, as well as in dendrites and cell bodies of interneurons of the dorsal cochlear nucleus, likely cartwheel cells. Quantitative immunogold immunocytochemistry revealed a pronounced distal to proximal gradient in the dendrosomatic distribution of Kv1. 4. In plasma membrane localizations, Kv1.4 was preferentially present in dendritic spines, either in the spine neck or in perisynaptic locations, always away from the postsynaptic density. These findings indicate that Kv1.4 is largely distributed in dendritic compartments of fusiform and cartwheel cells of the dorsal cochlear nucleus. Its preferential localization in dendritic spines, where granule cell axons make powerful excitatory synapses, suggests a role for this voltage-dependent ion Channel in the regulation of dendritic excitability and excitatory inputs.

Yiping Hsueh - One of the best experts on this subject based on the ideXlab platform.

  • requirement of n terminal cysteines of psd 95 for psd 95 multimerization and ternary complex formation but not for binding to Potassium Channel Kv1.4
    Journal of Biological Chemistry, 1999
    Co-Authors: Yiping Hsueh, Morgan Sheng
    Abstract:

    The PSD-95 family of PSD-95/Discs large/ZO-1 (PDZ) domain-containing proteins plays a role in the clustering and localization of specific ion Channels and receptors at synapses. Previous studies have shown that PSD-95 forms multimers through an N-terminal region (termed the N-segment) and that the multimerization of PSD-95 is critical for its ability to cluster Shaker-type Potassium Channel Kv1.4 in heterologous cells. We show here that the PSD-95 N-segment functions as a multimerization domain only when located at the N-terminal end of a heterologous protein. A pair of N-terminal cysteines, Cys3 and Cys5, is essential for the ability of PSD-95 to self-associate and to form cell surface clusters with Kv1.4. However, PSD-95 mutants lacking these cysteine residues retain their ability to associate with membranes and to bind to Kv1.4. Unlike wild type PSD-95, the cysteine mutant of PSD-95 cannot form a ternary complex with Kv1.4 and the cell adhesion molecule Fasciclin II. These results suggest that the N-terminal cysteines are essential for PSD-95 multimerization and that multimerization is required for simultaneous binding of multiple membrane protein ligands by PSD-95.

Rolfdetlef Treede - One of the best experts on this subject based on the ideXlab platform.

  • co expression of the voltage gated Potassium Channel Kv1.4 with transient receptor potential Channels trpv1 and trpv2 and the cannabinoid receptor cb1 in rat dorsal root ganglion neurons
    Neuroscience, 2006
    Co-Authors: U Binzen, Wolfgang Greffrath, S Hennessy, M Bausen, Sigrid Saalerreinhardt, Rolfdetlef Treede
    Abstract:

    Potassium Channels contribute to basic neuronal excitability and modulation. Here, we examined expression patterns of the voltage-gated Potassium Channel Kv1.4, the nociceptive transduction Channels TRPV1 and TRPV2 as well as the putative anti-nociceptive cannabinoid receptor CB1 by immunofluorescence double-labelings in sections of rat dorsal root ganglia (DRGs). Kv1.4, TRPV1 and CB1 were each detected in about one third of neurons (35.7+/-0.5%, 29.4+/-1.1% and 36.4+/-0.5%, respectively, mean diameter 19.1+/-0.3 microm). TRPV2 was present in 4.4+/-0.4% of all neurons that were significantly larger in diameter (27.4+/-0.7 microm; P < 0.001). Antibody double-labeling revealed that the majority of Kv1.4-positive neurons co-expressed TRPV1 (73.9+/-1.5%) whereas none expressed TRPV2. The largest overlap was found with CB1 (93.1+/-0.1%). CB1 expression resembled that seen for Kv1.4 since the majority of neurons expressing CB1-protein also expressed TRPV1 (69.4+/-6.5%) but not TRPV2 (0.6+/-0.3%). When CB1-mRNA was detected using in situ hybridizations an additional subset of larger neurons was labeled including 82.4+/-17.7% of the TRPV2 expressing neurons. However, co-localization of Kv1.4 with CB1-mRNA (92%, mean diameter: 18.5 microm) was essentially the same as with CB1-protein. The almost complete overlap of CB1 and Kv1.4 in nociceptive DRG neurons suggests a functional synergistic action between Kv1.4 and CB1. The Potassium Channel may have two important roles in nociception. As the molecular basis of A-type current it could be involved in the control of repetitive discharges at peripheral terminals and as a downstream signal transduction site of CB1 in the control of presynaptic transmitter release at central terminals.