scholarly journals Ankyrin-R regulates fast-spiking interneuron excitability through perineuronal nets and Kv3.1b K+ channels

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Sharon Stevens ◽  
Colleen M Longley ◽  
Yuki Ogawa ◽  
Lindsay Teliska ◽  
Anithachristy Arumanayagam ◽  
...  
Keyword(s):  
Cell Adhesion Molecules ◽  
Protein Complexes ◽  
Cytoskeletal Proteins ◽  
Intrinsic Excitability ◽  
Binding Motif ◽  
Perineuronal Nets ◽  
Dramatic Reduction ◽  
Fast Spiking ◽  
Firing Properties ◽  
Necessary And Sufficient

Neuronal ankyrins cluster and link membrane proteins to the actin and spectrin-based cytoskeleton. Among the three vertebrate ankyrins, little is known about neuronal Ankyrin-R (AnkR). We report AnkR is highly enriched in Pv+ fast-spiking interneurons in mouse and human. We identify AnkR-associated protein complexes including cytoskeletal proteins, cell adhesion molecules (CAMs), and perineuronal nets (PNNs). We show that loss of AnkR from forebrain interneurons reduces and disrupts PNNs, decreases anxiety-like behaviors, and changes the intrinsic excitability and firing properties of Pv+ fast-spiking interneurons. These changes are accompanied by a dramatic reduction in Kv3.1b K+ channels. We identify a novel AnkR-binding motif in Kv3.1b, and show that AnkR is both necessary and sufficient for Kv3.1b membrane localization in interneurons and at nodes of Ranvier. Thus, AnkR regulates Pv+ fast-spiking interneuron function by organizing ion channels, CAMs, and PNNs, and linking these to the underlying b1 spectrin-based cytoskeleton.

scholarly journals Ankyrin-R regulates fast-spiking interneuron excitability through perineuronal nets and Kv3.1b K+ channels

2021 ◽  
Author(s):  
Sharon R. Stevens ◽  
Colleen M. Longley ◽  
Yuki Ogawa ◽  
Lindsay H. Teliska ◽  
Anithachristy S. Arumanayagam ◽  
...  
Keyword(s):  
Cell Adhesion Molecules ◽  
Protein Complexes ◽  
Cytoskeletal Proteins ◽  
Intrinsic Excitability ◽  
Binding Motif ◽  
Perineuronal Nets ◽  
Dramatic Reduction ◽  
Fast Spiking ◽  
Firing Properties ◽  
Necessary And Sufficient

ABSTRACTNeuronal ankyrins cluster and link membrane proteins to the actin and spectrin-based cytoskeleton. Among the three vertebrate ankyrins, little is known about neuronal Ankyrin-R (AnkR). We report AnkR is highly enriched in Pv+ fast-spiking interneurons in mouse and human. We identify AnkR-associated protein complexes including cytoskeletal proteins, cell adhesion molecules (CAMs), and perineuronal nets (PNNs). We show that loss of AnkR from forebrain interneurons reduces and disrupts PNNs, decreases anxiety-like behaviors, and changes the intrinsic excitability and firing properties of Pv+ fast-spiking interneurons. These changes are accompanied by a dramatic reduction in Kv3.1b K+ channels. We identify a novel AnkR-binding motif in Kv3.1b, and show that AnkR is both necessary and sufficient for Kv3.1b membrane localization in interneurons and at nodes of Ranvier. Thus, AnkR regulates Pv+ fast-spiking interneuron function by organizing ion channels, CAMs, and PNNs, and linking these to the underlying β1 spectrin-based cytoskeleton.

scholarly journals Perineuronal nets decrease membrane capacitance of peritumoral fast spiking interneurons in a model of epilepsy

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Bhanu P. Tewari ◽  
Lata Chaunsali ◽  
Susan L. Campbell ◽  
Dipan C. Patel ◽  
Adam E. Goode ◽  
...  
Keyword(s):  
Membrane Capacitance ◽  
Perineuronal Nets ◽  
Fast Spiking

The sodium channel activator Lu AE98134 normalizes the altered firing properties of fast spiking interneurons in Dlx5/6+/− mice

2018 ◽  
Vol 662 ◽  
pp. 29-35 ◽  
Author(s):  
Nadia Lybøl von Schoubye ◽  
Kristen Frederiksen ◽  
Uffe Kristiansen ◽  
Anders Victor Petersen ◽  
Nils Ole Dalby ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Fast Spiking ◽  
Firing Properties ◽  
Channel Activator

scholarly journals Opposing Effects of a Tyrosine-Based Sorting Motif and a PDZ-Binding Motif Regulate Human T-Lymphotropic Virus Type 1 Envelope Trafficking

2010 ◽  
Vol 84 (14) ◽  
pp. 6995-7004 ◽  
Author(s):  
Anna Ilinskaya ◽  
Gisela Heidecker ◽  
David Derse
Keyword(s):  
Virus Type ◽  
Protein Complexes ◽  
Adaptor Protein ◽  
Degradation Pathway ◽  
Target Cells ◽  
Binding Motif ◽  
Wild Type ◽  
T Lymphotropic Virus ◽  
In Cells

ABSTRACT Human T-lymphotropic virus type 1 (HTLV-1) envelope (Env) glycoprotein mediates binding of the virus to its receptor on the surface of target cells and subsequent fusion of virus and cell membranes. To better understand the mechanisms that control HTLV-1 Env trafficking and activity, we have examined two protein-protein interaction motifs in the cytoplasmic domain of Env. One is the sequence YSLI, which matches the consensus YXXΦ motifs that are known to interact with various adaptor protein complexes; the other is the sequence ESSL at the C terminus of Env, which matches the consensus PDZ-binding motif. We show here that mutations that destroy the YXXΦ motif increased Env expression on the cell surface and increased cell-cell fusion activity. In contrast, mutation of the PDZ-binding motif greatly diminished Env expression in cells, which could be restored to wild-type levels either by mutating the YXXΦ motif or by silencing AP2 and AP3, suggesting that interactions with PDZ proteins oppose an Env degradation pathway mediated by AP2 and AP3. Silencing of the PDZ protein hDlg1 did not affect Env expression, suggesting that hDlg1 is not a binding partner for Env. Substitution of the YSLI sequence in HTLV-1 Env with YXXΦ elements from other cell or virus membrane-spanning proteins resulted in alterations in Env accumulation in cells, incorporation into virions, and virion infectivity. Env variants containing YXXΦ motifs that are predicted to have high-affinity interaction with AP2 accumulated to lower steady-state levels. Interestingly, mutations that destroy the YXXΦ motif resulted in viruses that were not infectious by cell-free or cell-associated routes of infection. Unlike YXXΦ, the function of the PDZ-binding motif manifests itself only in the producer cells; AP2 silencing restored the incorporation of PDZ-deficient Env into virus-like particles (VLPs) and the infectivity of these VLPs to wild-type levels.

scholarly journals Characterization of hCINAP, a Novel Coilin-interacting Protein Encoded by a Transcript from the Transcription Factor TAFIID32 Locus

2005 ◽  
Vol 280 (43) ◽  
pp. 36429-36441 ◽  
Author(s):  
Niovi Santama ◽  
Stephen C. Ogg ◽  
Anna Malekkou ◽  
Spyros E. Zographos ◽  
Karsten Weis ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Protein Complexes ◽  
Essential Gene ◽  
Single Copy ◽  
Cajal Body ◽  
Cajal Bodies ◽  
Binding Motif

Coilin is a marker protein for the Cajal body, a subnuclear domain acting as a site for assembly and maturation of nuclear RNA-protein complexes. Using a yeast two-hybrid screen to identify coilin-interacting proteins, we have identified hCINAP (human coilin interacting nuclear ATPase protein), a nuclear factor of 172 amino acids with a P-loop nucleotide binding motif and ATPase activity. The hCINAP protein sequence is highly conserved across its full-length from human to plants and yeast and is ubiquitously expressed in all human tissues and cell lines tested. The yeast orthologue of CINAP is a single copy, essential gene. Tagged hCINAP is present in complexes containing coilin in mammalian cells and recombinant, Escherichia coli expressed hCINAP binds directly to coilin in vitro. The 214 carboxyl-terminal residues of coilin appear essential for the interaction with hCINAP. Both immunofluorescence and fluorescent protein tagging show that hCINAP is specifically nuclear and distributed in a widespread, diffuse nucleoplasmic pattern, excluding nucleoli, with some concentration also in Cajal bodies. Overexpression of hCINAP in HeLa cells results in a decrease in the average number of Cajal bodies per nucleus, consistent with it affecting either the stability of Cajal bodies and/or their rate of assembly. The hCINAP mRNA is an alternatively spliced transcript from the TAF9 locus, which encodes the basal transcription factor subunit TAFIID32. However, hCINAP and TAFIID32 mRNAs are translated from different ATG codons and use distinct reading frames, resulting in them having no identity in their respective protein sequences.

scholarly journals Zyxin Interacts with the SH3 Domains of the Cytoskeletal Proteins LIM-nebulette and Lasp-1

2004 ◽  
Vol 279 (19) ◽  
pp. 20401-20410 ◽  
Author(s):  
Bo Li ◽  
Lei Zhuang ◽  
Beat Trueb
Keyword(s):  
Binding Site ◽  
Focal Adhesions ◽  
Sh3 Domain ◽  
Cytoskeletal Proteins ◽  
Site Directed Mutagenesis ◽  
Binding Motif ◽  
Sh3 Domains ◽  
Sorting Nexin ◽  
Sarcomeric Protein ◽  
Co Precipitation

Zyxin is a versatile component of focal adhesions in eukaryotic cells. Here we describe a novel binding partner of zyxin, which we have named LIM-nebulette. LIM-nebulette is an alternative splice variant of the sarcomeric protein nebulette, which, in contrast to nebulette, is expressed in non-muscle cells. It displays a modular structure with an N-terminal LIM domain, three nebulin-like repeats, and a C-terminal SH3 domain and shows high similarity to another cytoskeletal protein, Lasp-1 (LIM and SH3 protein-1). Co-precipitation studies and results obtained with the two-hybrid system demonstrate that LIM-nebulette and Lasp-1 interact specifically with zyxin. Moreover, the SH3 domain from LIM-nebulette is both necessary and sufficient for zyxin binding. The SH3 domains from Lasp-1 and nebulin can also interact with zyxin, but the SH3 domains from more distantly related proteins such as vinexin and sorting nexin 9 do not. On the other hand, the binding site in zyxin is situated at the extreme N terminus as shown by site-directed mutagenesis. LIM-nebulette and Lasp-1 use the same linear binding motif. This motif shows some similarity to a class II binding site but does not contain the classical PXXP sequence. LIM-nebulette reveals a subcellular distribution at focal adhesions similar to Lasp-1. Thus, LIM-nebulette, Lasp-1, and zyxin may play an important role in the organization of focal adhesions.

Function of Specific K+ Channels in Sustained High-Frequency Firing of Fast-Spiking Neocortical Interneurons

1999 ◽  
Vol 82 (5) ◽  
pp. 2476-2489 ◽  
Author(s):  
A. Erisir ◽  
D. Lau ◽  
B. Rudy ◽  
C. S. Leonard
Keyword(s):  
Firing Rate ◽  
High Frequency ◽  
Spike Trains ◽  
Firing Frequency ◽  
Channel Inactivation ◽  
Spike Shape ◽  
Fast Spiking ◽  
Firing Properties ◽  
Action Potential Repolarization

Fast-spiking GABAergic interneurons of the neocortex and hippocampus fire high-frequency trains of brief action potentials with little spike-frequency adaptation. How these striking properties arise is unclear, although recent evidence suggests K+ channels containing Kv3.1-Kv3.2 proteins play an important role. We investigated the role of these channels in the firing properties of fast-spiking neocortical interneurons from mouse somatosensory cortex using a pharmacological and modeling approach. Low tetraethylammonium (TEA) concentrations (≤1 mM), which block only a few known K+channels including Kv3.1-Kv3.2, profoundly impaired action potential repolarization and high-frequency firing. Analysis of the spike trains evoked by steady depolarization revealed that, although TEA had little effect on the initial firing rate, it strongly reduced firing frequency later in the trains. These effects appeared to be specific to Kv3.1 and Kv3.2 channels, because blockade of dendrotoxin-sensitive Kv1 channels and BK Ca2+-activated K+ channels, which also have high TEA sensitivity, produced opposite or no effects. Voltage-clamp experiments confirmed the presence of a Kv3.1-Kv3.2–like current in fast-spiking neurons, but not in other interneurons. Analysis of spike shape changes during the spike trains suggested that Na+ channel inactivation plays a significant role in the firing-rate slowdown produced by TEA, a conclusion that was supported by computer simulations. These findings indicate that the unique properties of Kv3.1-Kv3.2 channels enable sustained high-frequency firing by facilitating the recovery of Na+ channel inactivation and by minimizing the duration of the afterhyperpolarization in neocortical interneurons.

scholarly journals Diurnal changes in perineuronal nets and parvalbumin neurons in the rat medial prefrontal cortex

2020 ◽  
Author(s):  
John H. Harkness ◽  
Angela E. Gonzalez ◽  
Priyanka N. Bushana ◽  
Emily T. Jorgensen ◽  
Deborah M. Hegarty ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Active Phase ◽  
Autism Spectrum ◽  
Diurnal Rhythms ◽  
Oxidative Stress Marker ◽  
Perineuronal Nets ◽  
Diurnal Changes ◽  
Strong Trend ◽  
Fast Spiking

ABSTRACTPerineuronal nets (PNNs) surrounding fast-spiking, parvalbumin (PV) inhibitory interneurons are vital for providing excitatory:inhibitory balance within cortical circuits, and this balance is impaired in disorders such as schizophrenia, autism spectrum disorder, and substance use disorders. These disorders are also associated with altered diurnal rhythms, yet few studies have examined the diurnal rhythms of PNNs or PV cells. We measured the intensity and number of PV cells and PNNs labeled with Wisteria floribunda agglutinin (WFA) in the rat prelimbic medial prefrontal cortex (mPFC) at Zeitgeber times (ZT) ZT0, 6, 12, and 18. We also measured the oxidative stress marker 8-oxo-deoxyguanosine (8-oxo-dG). Relative to ZT0, the intensities of PNN and PV staining were increased in the dark (active) phase compared with the light (inactive) phase. The intensity of 8-oxo-dG was decreased from ZT0 at all time points (ZT6,12,18), in both PV cells and non-PV cells. To examine corresponding changes in inhibitory and excitatory inputs, we measured GAD 65/67 and vGlut1 puncta apposed to PV cells with and without PNNs. Relative to ZT6, there were more excitatory puncta on PV cells surrounded by PNNs at ZT18, but no changes in PV cells devoid of PNNs. No changes in inhibitory puncta were observed. Whole-cell slice recordings in fast-spiking (PV) cells with PNNs showed an increased ratio of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor:N-methyl-D-aspartate receptor (AMPA:NMDA) at ZT18 vs. ZT6. The number of PV cells and co-labeled PV/PNN cells containing the transcription factor orthodenticle homeobox 2 (OTX2), which maintains PNNs, showed a strong trend toward an increase from ZT6 to ZT18. These diurnal fluctuations in PNNs and PV cells are expected to alter cortical excitatory:inhibitory balance and provide new insights into treatment approaches for diseases impacted by imbalances in sleep and circadian rhythms.

scholarly journals OTME-20. Chitinase-3-like-1(CHI3L1) Protein Complexes Regulate the immunosuppressive Microenvironment in Glioblastoma

2021 ◽  
Vol 3 (Supplement_2) ◽  
pp. ii17-ii18
Author(s):  
Apeng Chen ◽  
Yinan Jiang ◽  
Zhengwei Li ◽  
Xiangwei Xiao ◽  
Dean Yimlamai ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Evasion ◽  
Protein Complexes ◽  
Immune Surveillance ◽  
Cell Infiltration ◽  
Binding Motif ◽  
T Cell Infiltration ◽  
Pathway Activation ◽  
Galectin 3 ◽  
Immunosuppressive Microenvironment

Abstract Glioblastoma (GBM) is the most common and highly malignant brain tumor in adults. Despite advances in multimodal treatment, GBM remains largely incurable. While immunotherapies have been highly effective in some types of cancer, the disappointing results from clinical trials for GBM immunotherapy represent continued challenges. GBM is highly immunosuppressive and resistant to immunotherapy because of glioma cells escaping from immune surveillance by reprograming the tumor microenvironment (TME). However, understanding the mechanisms of immune evasion by GBM remains elusive. Based on unbiased approaches, we found that Chitinase-3-like-1 (CHI3L1), also known as human homolog YKL-40, is highly expressed in GBM, which is regulated by the CHI3L1-PI3K/AKT/mTOR signaling in a positive feedback loop. Gain- and loss-function studies reveal that CHI3L1 plays a predominant role in regulating an immunosuppressive microenvironment by reprogramming tumor-associated macrophages (TAMs). Using the liquid chromatography-mass spectrometry and orthogonal structure-based screening, we found that Galectin-3 binding protein (Gal3BP) and its binding partner, Galectin-3 (Gal3), can interact competitively with the same binding motif on CHI3L1, leading to selective migration of M2-like versus M1-like bone marrow-derived macrophages (BMDMs) and resident microglia (MG). Mechanistically, the CHI3L1-Gal3 protein complex governs a transcriptional program of NFκB/CEBPβ to control the protumor phenotype of BMDMs, leading to inhibition of T cell infiltration and activation in the GBM TME. However, Gal3BP can reverse CHI3L1-Gal3 induced signaling pathway activation and subsequent protumor phenotype in TAMs. Based on protein binding motifs, a newly developed Gal3BP mimetic peptide can attenuate immune suppression and tumor progression in the syngeneic GBM mouse models, including decreasing M2-like TAMs and increasing M1-like TAMs and T cell infiltration. Together, these results shed light on the role of CHI3L1 protein complexes in immune evasion by glioblastoma and as a potential immunotherapeutic target for this devastating disease.

scholarly journals Tol-Dependent Macromolecule Import through the Escherichia coli Cell Envelope Requires the Presence of an Exposed TolA Binding Motif

2005 ◽  
Vol 187 (21) ◽  
pp. 7526-7534 ◽  
Author(s):  
Stéphanie Pommier ◽  
Marthe Gavioli ◽  
Eric Cascales ◽  
Roland Lloubès
Keyword(s):  
Escherichia Coli ◽  
Protein Complexes ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Binding Activity ◽  
Binding Motif ◽  
Cell Integrity ◽  
Outer Membranes

ABSTRACT The Tol-Pal proteins of the cell envelope of Escherichia coli are required for maintaining outer membrane integrity. This system forms protein complexes in which TolA plays a central role by providing a bridge between the inner and outer membranes via its interaction with the Pal lipoprotein. The Tol proteins are parasitized by filamentous bacteriophages and group A colicins. The N-terminal domain of the Ff phage g3p protein and the translocation domains of colicins interact directly with TolA during the processes of import through the cell envelope. Recently, a four-amino-acid sequence in Pal has been shown to be involved in Pal's interaction with TolA. A similar motif is also present in the sequence of two TolA partners, g3p and colicin A. Here, a mutational study was conducted to define the function of these motifs in the binding activity and import process of TolA. The various domains were produced and exported to the bacterial periplasm, and their cellular effects were analyzed. Cells producing the g3p domain were tolerant to colicins and filamentous phages and had destabilized outer membranes, while g3p deleted of three residues in the motif was affected in TolA binding and had no effect on cell integrity or colicin or phage import. A conserved Tyr residue in the colicin A translocation domain was involved in TolA binding and colicin A import. Furthermore, in vivo and in vitro coprecipitation analyses demonstrated that colicin A and g3p N-terminal domains compete for binding to TolA.

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