Amino Acids, Peptides, and Proteins Commons^™

Radiogenomic Profiling Of Prostate Tumors Prior To External Beam Radiotherapy Converges On A Transcriptomic Signature Of Tgf-Β Activity Driving Tumor Recurrence, Anson T. Ku, Uma Shankavaram, Shana Y. Trostel, Hong Zhang, Sumeyra Kartal, Houssein A. Sater, Stephanie A. Harmon, Nicole V. Carrabba, Yang Liu, Hyunnam Ryu, James A. Proudfoot, Boon Hao Hong, Bradford J. Wood, Peter A. Pinto, Peter L. Choyke, Mack Roach, Howard M. Sandler, Stephanie L. Pugh, Kenneth L. Zeitzer, Lucas C. Mendez, Nirav S. Kapadia, William A. Hall, Anand B. Desai, Radka S. Stoyanova, Alan Pollack, Elai Davicioni, Melvin L. K. Chua, Baris Turkbey, Adam G. Sowalsky, Deborah E. Citrin

Einstein Health Papers

PURPOSE: Clinical risk grouping based on PSA, tumor grade, and disease extent guides treatment intensity for localized prostate cancer. However, many patients with intermediate- or high-risk disease treated with external beam radiotherapy (EBRT) and androgen deprivation therapy (ADT) still develop biochemical recurrence (BCR). Early identification of patients at high risk for BCR could enable personalized treatment strategies.

EXPERIMENTAL DESIGN: We prospectively enrolled 29 patients with intermediate- or high-risk prostate cancer undergoing EBRT and ADT. Pretreatment biopsies (n = 60) underwent whole-transcriptome microarray and whole-exome sequencing. Patients received multiparametric MRI at baseline and 6 months after treatment, with a median follow-up …

Increased Intermembrane Space [Ca2+] Drives Mitochondrial Structural Damage In Cpvt, Shanna Hamilton, Radmila Terentyeva, Roland Veress, Fruzsina Perger, Zuzana Nichtova, Mark Bannister, Jinxi Wang, Sage Quiggle, Rachel Battershell, Matthew Gorr, Sandor Györke, Bum-Rak Choi, Christopher George, Andriy Belevych, György Csordás, Dmitry Terentyev

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Mitochondrial dysfunction caused by abnormally high RyR2 (ryanodine receptor) activity is a common finding in cardiovascular diseases. Mechanisms linking RyR2 gain of function with mitochondrial remodeling remain elusive. We hypothesized that RyR2 hyperactivity in cardiac disease increases [Ca 2+ ] in the mitochondrial intermembrane space (IMS) and activates the Ca 2+ -sensitive protease calpain, driving remodeling of mitochondrial cristae architecture through cleavage of structural protein OPA1 (optic atrophy protein 1).

METHODS: We generated a highly arrhythmogenic rat model of catecholaminergic polymorphic ventricular tachycardia, induced by RyR2 gain-of-function mutation S2236L(Ser2336Leu)(+/-) . We created a new biosensor to measure IMS-[Ca2+ ] …

Protein-Protein Interaction–Interfering Peptide Rescues Dysregulated Nmda Receptor Signaling, Robert E. Featherstone, Hongbin Li, Ameet S. Sengar, Karin E. Borgmann-Winter, Olya Melnychenko, Lindsey M. Crown, Ray L. Gifford, Felix Amirfathi, Anamika Banerjee, Aivi Tran, Krishna Parekh, Margaret Heller, Wenyu Zhang, Robert J. Gallop, Adam D. Marc, Pragya Komal, Michael W. Salter, Steven J. Siegel, Chang-Gyu Hahn

Farber Institute for Neuroscience Faculty Papers

The complex and heterogeneous genetic architecture of neuropsychiatric illnesses compels us to look beyond individual risk genes for therapeutic strategies and target the interactive dynamics and convergence of their protein products. A mechanistic substrate for convergence of synaptic neuropsychiatric risk genes are protein-protein interactions (PPIs) in the N-methyl-D-aspartate receptor (NMDAR) complex. NMDAR hypofunction in schizophrenia is associated with hypoactivity of Src kinase, resulting from convergent alterations in PPIs of Src with its partners. Of these, the association of Src with PSD-95, which inhibits the activity of this kinase in the NMDAR complex, is known to be increased in schizophrenia. Here, …

Concurrent Local Therapy Extends Clinical Benefit Of Tebentafusp In Metastatic Uveal Melanoma Patients, Tristan L. Lim, Kamaneh Montazeri, Eric Wehrenberg-Klee, Antoine Desilets, Rino S. Seedor, Marlana Orloff, Takami Sato, Michael Caplan, Mariam El-Ashmawy, Benjamin Izar, Shaheer Khan, Inderjit Mehmi, Aleigha Lawless, Theodore S. Hong, Omid Hamid, Richard D. Carvajal, Alexander Shoushtari, Ryan J. Sullivan

Kimmel Cancer Center Faculty Papers

BACKGROUND: Tebentafusp has significantly improved overall survival in HLA-A*02:01+ metastatic uveal melanoma (mUM) patients even in those with a best objective response of progressive disease. Thus, strategies to maintain tebentafusp therapy are critical. Here, we examine the efficacy and safety of adding concurrent local therapy (CLT) to tebentafusp upon radiological progression with tebentafusp alone.

PATIENTS AND METHODS: This multicenter retrospective study included mUM patients treated with tebentafusp and CLT, consisting of extrahepatic soft tissue irradiation and liver-directed therapies (LDTs). Efficacy of target and nontarget sites were assessed per RECIST version 1.1. PFS with tebentafusp alone (PFS1) was compared to that …

Uncovering The Pml::Rara Fusion In Cytogenetically Cryptic And Fish-Negative Acute Promyelocytic Leukemia-A Case Report And Comprehensive Literature Review, Busra Delikkaya, Jaime Eberle-Singh, Arianna Morton, Jerald Gong, Jinglan Liu

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

The PML::RARA fusion resulting from t(15;17) is the genetic hallmark of acute promyelocytic leukemia (APL), typically detected by cytogenetics and/or fluorescence in situ hybridization (FISH) studies. Rarely, APL patients present with normal cytogenetics and FISH findings, complicating diagnosis and delaying life-saving therapy. We report a 23-year-old male with clinical, morphologic and immunophenotypic features consistent with APL but negative for FISH studies. Despite prompt initiation of all-trans retinoic acid (ATRA) based on clinical suspicion, the patient succumbed to intracranial hemorrhage. Quantitative reverse transcriptase PCR (qRT-PCR) confirmed a long isoform PML::RARA fusion. A review of 34 published cytogenetics- and FISH-negative cases since …

Non-Invasive Detection Of Choroidal Melanoma Via Tear-Derived Protein Corona On Gold Nanoparticles: A Machine Learning Approach, Hakimeh Rakhshandeh, Ahmad Nasiraei, Hamid Riazi-Esfahani, Babak Masoomian, Fariba Ghassemi, Mojtaba Arjmand, Saeed Heidari Keshel, Fatemeh Atyabi, Rassoul Dinarvand

Wills Eye Hospital Papers

This study investigates the feasibility of using tear sample analysis, based on protein corona formation on gold nanoparticles combined with electrospray ionization mass spectrometry (ESI-MS) and machine learning techniques, as a non-invasive approach for the detection of choroidal melanoma. The aim is to assess whether protein-nanoparticle interactions can support early and reliable identification of this ocular condition. Tear samples were collected using Schirmer strips from six healthy individuals and six patients diagnosed with choroidal melanoma, with subsequent augmentation to 18 samples per group. Gold nanoparticles (AuNPs, ~ 20 nm) were synthesized via citrate reduction and incubated with tear samples to …

Templating Of Monomeric Alpha-Synuclein Results In Inflammation And Snpc Dopamine Neuron Death In A Genetic Mouse Model Of Induced Synucleinopathy, Matthew D. Byrne, Peyman Petramfar, Jae-Kyung Lee, Richard J. Smeyne

Department of Neuroscience Faculty Papers

While the etiology of most cases of Parkinson's disease (PD) are idiopathic, it has been estimated that 5-10% of PD arise from known genetic mutations. The first mutations described that leads to the development of an autosomal dominant form of PD are in the SNCA gene that codes for the protein alpha-synuclein (α-syn). α-syn is an abundant presynaptic protein that is natively disordered and whose function is still unclear. In PD, α-syn misfolds into multimeric b-pleated sheets that aggregate in neurons (Lewy Bodies/neurites) and spread throughout the neuraxis in a pattern that aligns with disease progression. Here, using IHC, HC, …

Sirt6 Deficiency Promotes Senescence And Age-Associated Intervertebral Disc Degeneration In Mice, Pranay Ramteke, Bahiyah Watson, Mallory Toci, Victoria Tran, Shira N Johnston, Maria Tsingas, Ruteja Barve, Ramkrishna Mitra, Richard Loeser, John Collins, Makarand Risbud

Department of Orthopaedic Surgery Faculty Papers

Intervertebral disc degeneration is a major risk factor contributing to chronic low back and neck pain. While the etiological factors for disc degeneration vary, age is still one of the most important risk factors. Recent studies have shown the promising role of SIRT6 in mammalian aging and skeletal tissue health, however its role in the intervertebral disc health remains unexplored. We investigated the contribution of SIRT6 to disc health by studying the age-dependent spinal phenotype of mice with conditional deletion of Sirt6 in the disc (Acan^CreERT2; Sirt6^fl/fl). Histological studies showed a degenerative phenotype in knockout mice …

Evolution Of The Tumor Immune Landscape During Treatment With Tebentafusp, A T Cell Receptor-Cd3 Bispecific, Joseph Sacco, Peter Kirk, Emma Leach, Alexander Shoushtari, Richard Carvajal, Camille Britton-Rivet, Sophie Khakoo, Laura Collins, Luis De La Cruz-Merino, Zeynep Eroglu, Alexandra Ikeguchi, Paul Nathan, Omid Hamid, Marcus Butler, Sarah Stanhope, Koustubh Ranade, Takami Sato

Department of Medical Oncology Faculty Papers

Metastatic uveal melanoma is an aggressive disease with poor outcome, which is refractory to immune checkpoint inhibitors. A T cell receptor (TCR)-based CD3 bispecific, tebentafusp, delivers clinical benefit in patients with metastatic uveal melanoma. Understanding the molecular basis for the anti-tumor activity of tebentafusp in an indication where checkpoint inhibitors are ineffective could aid in identification of other solid tumor indications where CD3 bispecifics may serve an unmet need. By analyzing tumor biopsies taken prior to treatment, early on-treatment, and at progression (NCT02570308), using RNA sequencing (RNA-seq) and immunohistochemistry (IHC), we show that expression of interferon-related genes in the tumor …

Radial Glia Integrin Avb8 Regulates Cell Autonomous Microglial Tgfβ1 Signaling That Is Necessary For Microglial Identity, Gabriel Mckinsey, Nicolas Santander, Xiaoming Zhang, Kilian Kleemann, Lauren Tran, Aditya Katewa, Kaylynn Conant, Matthew Barraza, Kian Waddell, Carlos Lizama, Marie La Russa, Ji Hyun Koo, Hyunji Lee, Dibyanti Mukherjee, Helena Paidassi, E. S. Anton, Kamran Atabai, Dean Sheppard, Oleg Butovsky, Thomas Arnold

Department of Medicine Faculty Papers

Microglial diversity arises from the interplay between inherent genetic programs and external environmental signals. However, the mechanisms by which these processes develop and interact within the growing brain are not yet fully understood. Here, we show that radial glia-expressed integrin beta 8 (ITGB8) activates microglia-expressed TGFβ1 to drive microglial development. Domain-restricted deletion of Itgb8 in these progenitors results in regionally restricted and developmentally arrested microglia that persist into adulthood. In the absence of autocrine TGFβ1 signaling, microglia adopt a similar phenotype, leading to neuromotor symptoms almost identical to Itgb8 mutant mice. In contrast, microglia lacking the canonical TGFβ signal transducers …

Vdac2 And Bak Scarcity In Liver Mitochondria Enables Targeting Hepatocarcinoma While Sparing Hepatocytes, Shamim Naghdi, Piyush Mishra, Soumya S. Roy, David Weaver, Ludivine Walter, Erika Davies, Anil N. Antony, Xuena Lin, Gisela Moehren, Mark A. Feitelson, Christopher A. Reed, Tullia Lindsten, Craig B. Thompson, Hien T. Dang, Jan B. Hoek, Erik S. Knudsen, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Differences between normal tissues and invading tumors that allow tumor targeting while saving normal tissue are much sought after. Here we show that scarcity of VDAC2, and the consequent lack of Bak recruitment to mitochondria, renders hepatocyte mitochondria resistant to permeabilization by truncated Bid (tBid), a Bcl-2 Homology 3 (BH3)-only, Bcl-2 family protein. Increased VDAC2 and Bak is found in most human liver cancers and mitochondria from tumors and hepatic cancer cell lines exhibit VDAC2- and Bak-dependent tBid sensitivity. Exploring potential therapeutic targeting, we find that combinations of activators of the tBid pathway with inhibitors of the Bcl-2 family proteins …

Combination Of Hsp90 Inhibitors And Hsp70 Inducers Prevent Hydrochloric Acid-Induced Pulmonary Fibrosis In Rabbits, Ruben M. L. Colunga Biancatelli, Pavel A. Solopov, Tierney Day, Dan E. Austin Jr., Len E. Murray, John D. Catravas

Bioelectrics Publications

Combined therapies with Heat Shock Protein 90 (HSP90) inhibitors and Heat Shock Protein 70 (HSP70) inducers are gaining significant interest in cancer and cardiovascular research. Here, we tested the hypothesis that HSP90 inhibitors and HSP70 inducers, together, can block the development of pulmonary fibrosis. We exposed New Zealand White Rabbits to hydrochloric acid (HCl, 0.1 N, 1.5 mL/kg), one of the top five chemicals most commonly involved in accidental exposures and inhalation injuries worldwide, and treated animals with either the orally available HSP90 inhibitor TAS-116 (1.7 mg/kg 5x/week) or TAS-116 combined with the HSP70 inducer, geranylgeranyl acetone (GGA, 50 mg/kg, …

Treatment Sequence With Tebentafusp And Immune Checkpoint Inhibitors In Patients With Metastatic Uveal Melanoma And Metastatic Gna11/Gnaq Mutant Melanocytic Tumors, Florentia Dimitriou, Marlana Orloff, Erica Koch Hein, Phil Cheng, Isaac Hughes, Ester Simeone, Kamaneh Montazeri, Piyush Grover, Inderjit Mehmi, Camille Gerard, Caroline Gaudy-Marqueste, Jean-Jacques Grob, Olivier Michielin, Omid Hamid, Georgina Long, Ryan Sullivan, Ellen Kapiteijn, Douglas Johnson, Paolo Ascierto, Anthony Joshua, Richard Carvajal, Marcus Butler, Jessica Hassel, Reinhard Dummer

Kimmel Cancer Center Faculty Papers

BACKGROUND: Metastatic uveal melanoma (mUM) is rare. Immune checkpoint inhibitors (ICIs) have shown modest efficacy in mUM. Tebentafusp prolonged overall survival (OS) in a phase 3 study. We aimed to investigate the efficacy and safety of the sequence of tebentafusp and ICIs.

METHODS: Patients with HLA-A * 02:01 positive mUM, or metastatic GNA11/GNAQ mutant melanocytic tumors treated with tebentafusp followed by ICIs (group 1) or the inverse sequence (group 2) at any treatment line were retrospectively identified. The primary objective was OS rate at 2 years.

RESULTS: 131 patients were included; 51 in group 1 and 80 in group 2. …

Changes In Cardiovascular Risk Factors And Health Care Expenditures Among Patients Prescribed Semaglutide, Yuan Lu, Yuntian Lu, Tedi Totojani, Chungsoo Kim, Rohan Khera, Hua Xu, John E. Brush Jr., Harlan M. Krumholtz, Jason Abaluck

Department of Medicine Faculty Publications

Importance Semaglutide, a glucagon-like peptide-1 receptor agonist, has demonstrated substantial weight reduction and cardiovascular benefits in clinical trials. However, its association with clinical outcomes and health care expenditures remains underexplored.

Objective To evaluate changes in cardiovascular risk factors and health care expenditures among patients prescribed semaglutide across multicenter cohorts.

Design, Setting, and Participants This retrospective cohort study included 23 522 adults (≥18 years) who received an initial semaglutide prescription between January 1, 2018, and January 1, 2025, at Sentara Healthcare and between January 1, 2018, and May 1, 2025, at Yale New Haven Health System.

Exposure The first prescription of …

Nuclear Expression Of Dynamin 2 Is Associated With Tumor Aggressiveness In Bladder Cancer Patients: A Bioinformatics And Experimental Approach, Mahdieh Razmi, Leili Saeednejad Zanjani, Mandana Rahimi, Roya Sajed, Sadegh Safaei, Zahra Madjd, Roya Ghods

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Dynamin 2 (DNM2) is aberrantly expressed in different malignancies and exerts a function in tumor progression.

AIMS: This study, for the first time, aimed to evaluate the clinical and prognostic value of DNM2 in the pathophysiology of bladder cancer using bioinformatics analysis and experimental evaluation.

METHODS AND RESULTS: We analyzed gene expression of DNM2 in bladder tumor by GEPIA2 and GENT2 platforms. Cluster subnetworks were recognized from the protein-protein interaction (PPI) network using the MCODE plugin to screen the key genes. Subsequently, the pathway enrichment analysis was evaluated. Then, the immunohistochemical examination was conducted on 209 paraffin-embedded bladder cancer …

Expression Of The Αvβ3 Integrin Affects Prostate Cancer Sev Cargo And Density And Promotes Sev Pro-Tumorigenic Activity In Vivo Through A Gpi-Anchored Receptor, Ngr2, Cecilia Verrillo, Fabio Quaglia, Christopher Shields, Stephen Lin, Andrew Kossenkov, Hsin-Yao Tang, David Speicher, Nicole Naranjo, Anna Testa, William Kelly, Qin Liu, Benjamin Leiby, Luca Musante, Khalid Sossey-Alaoui, Navneet Dogra, Tzu-Yi Chen, Dario Altieri, Lucia Languino

Department of Pharmacology, Physiology, and Cancer Biology Faculty Papers

It is known that small extracellular vesicles (sEVs) are released from cancer cells and contribute to cancer progression via crosstalk with recipient cells. We have previously reported that sEVs expressing the αVβ3 integrin, a protein upregulated in aggressive neuroendocrine prostate cancer (NEPrCa), contribute to neuroendocrine differentiation (NED) in recipient cells. Here, we examine the impact of αVβ3 expression on sEV protein content, density and function. sEVs used in this study were isolated by iodixanol density gradients and characterized by nanoparticle tracking analysis, immunoblotting and single vesicle analysis. Our proteomic profile of sEVs containing αVβ3 shows downregulation of typical effectors involved …

Evidence Of Direct Interaction Between Cisplatin And The Caspase-Cleaved Prostate Apoptosis Response-4 Tumor Suppressor, Krishna K. Raut, Samjhana Pandey, Gyanendra Kharel, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Prostate apoptosis response-4 (Par-4) tumor suppressor protein has gained attention as a potential therapeutic target owing to its unique ability to selectively induce apoptosis in cancer cells, sensitize them to chemotherapy and radiotherapy, and mitigate drug resistance. It has recently been reported that Par-4 interacts synergistically with cisplatin, a widely used anticancer drug. However, the mechanistic details underlying this relationship remain elusive. In this investigation, we employed an array of biophysical techniques, including circular dichroism spectroscopy, dynamic light scattering, and UV–vis absorption spectroscopy, to characterize the interaction between the active caspase-cleaved Par-4 (cl-Par-4) fragment and cisplatin. Additionally, elemental analysis was …

Assessment Of Physical Fitness After Bariatric Surgery And Its Association With Protein Intake And Type Of Cholecalciferol Supplementation, Hendrika J M Smelt, Sjaak Pouwels, Alper Celik, Adarsh Gupta, Johannes F Smulders

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Background: Several studies showed that there is a relationship between vitamin and mineral status and muscle strength. In particular this is the case for handgrip strength (HS) and vitamin D deficiency. In bariatric surgery there is a risk of decrease in muscle strength after surgery and also vitamin and mineral deficiencies are not uncommon. The aim of this study is to assess the effect of low vitamin 25 (OH) cholecalciferol levels, high dose cholecalciferol supplementation regime and protein intake on physical fitness, measured using handgrip strength (HS) and the shuttle walk run test (SWRT). Methods: For this retrospective …

Genotype-Phenotype Study In Patients With Valosin-Containing Protein Mutations Associated With Multisystem Proteinopathy, Ebaa Al-Obeidi, Sejad Al-Tahan, Abhilasha Surampalli, Namita Goyal, Annabel K. Wang, Andreas Hermann, Molly Omizo, Charles D. Smith, Tahseen Mozaffar, Virginia Kimonis

Neurology Faculty Publications

Mutations in valosin‐containing protein (VCP), an ATPase involved in protein degradation and autophagy, cause VCP disease, a progressive autosomal dominant adult onset multisystem proteinopathy. The goal of this study is to examine if phenotypic differences in this disorder could be explained by the specific gene mutations. We therefore studied 231 individuals (118 males and 113 females) from 36 families carrying 15 different VCP mutations. We analyzed the correlation between the different mutations and prevalence, age of onset and severity of myopathy, Paget's disease of bone (PDB), and frontotemporal dementia (FTD), and other comorbidities. Myopathy, PDB and FTD was present in …

Taurine's Effect On Cocaine Reward And Neurogenesis In The Adolescent Male Rat Brain., Avery E. Villa-Gonzalez

Dissertations and Theses

Adolescence is a developmentally critical transition from childhood to adulthood including both maturation of the body and the brain. Neuroplastic changes result in dynamic organization of the brain during adolescence, leaving them vulnerable to development of mental illness and drug-seeking behavior. According to the United Nations Office on Drugs and Crime, the psychostimulant cocaine is the second most popular illicit drug in the world. Cocaine, amongst having many detrimental effects, has shown to also decrease hippocampal neurogenesis, resulting in decreased neuroplasticity and cognitive dysfunction. Previous students in our laboratory have shown that treatment of adult male rats with the essential …

Expanding The Phenotype Associated With Naa10-Related N-Terminal Acetylation Deficiency., Chloé Saunier, Svein Isungset Støve, Bernt Popp, Bénédicte Gérard, Marina Blenski, Nicholas Ahmew, +Several Additional Authors

Pediatrics Faculty Publications

N-terminal acetylation is a common protein modification in eukaryotes associated with numerous cellular processes. Inherited mutations in NAA10, encoding the catalytic subunit of the major N-terminal acetylation complex NatA have been associated with diverse, syndromic X-linked recessive disorders, whereas de novo missense mutations have been reported in one male and one female individual with severe intellectual disability but otherwise unspecific phenotypes. Thus, the full genetic and clinical spectrum of NAA10 deficiency is yet to be delineated. We identified three different novel and one known missense mutation in NAA10, de novo in 11 females, and due to maternal germ …

Urotensin Ii Modulates Rapid Eye Movement Sleep Through Activation Of Brainstem Cholinergic Neurons, Salvador Huitron-Resendiz, Morten P. Kristensen, Stephen L. Grupke, Christopher Tyler, Olivier Civelli, Christopher S. Leonard, Luis De Lecea

NYMC Faculty Publications

Urotensin II (UII) is a cyclic neuropeptide with strong vasoconstrictive activity in the peripheral vasculature. UII receptor mRNA is also expressed in the CNS, in particular in cholinergic neurons located in the mesopontine tegmental area, including the pedunculopontine tegmental (PPT) and lateral dorsal tegmental nuclei. This distribution suggests that the UII system is involved in functions regulated by acetylcholine, such as the sleep-wake cycle. Here, we tested the hypothesis that UII influences cholinergic PPT neuron activity and alters rapid eye movement (REM) sleep patterns in rats. Local administration of UII into the PPT nucleus increases REM sleep without inducing changes …

Impaired Fast-Spiking, Suppressed Cortical Inhibition, And Increased Susceptibility To Seizures In Mice Lacking Kv3.2 K+ Channel Proteins, David Lau, Eleazar Vega-Saenz De Miera, Diego Contreras, Alan Chow, Richard Paylor, Christopher S. Leonard, Bernardo Rudy

NYMC Faculty Publications

Voltage-gated K(+) channels of the Kv3 subfamily have unusual electrophysiological properties, including activation at very depolarized voltages (positive to -10 mV) and very fast deactivation rates, suggesting special roles in neuronal excitability. In the brain, Kv3 channels are prominently expressed in select neuronal populations, which include fast-spiking (FS) GABAergic interneurons of the neocortex, hippocampus, and caudate, as well as other high-frequency firing neurons. Although evidence points to a key role in high-frequency firing, a definitive understanding of the function of these channels has been hampered by a lack of selective pharmacological tools. We therefore generated mouse lines in which one …