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Kumar K, Basak R, Rai A, Mukhopadhyay A. GRASP negatively regulates the secretion of the virulence factor gp63 in Leishmania. Mol Microbiol 2024; 121:1063-1078. [PMID: 38558112 DOI: 10.1111/mmi.15255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
Metalloprotease-gp63 is a virulence factor secreted by Leishmania. However, secretory pathway in Leishmania is not well defined. Here, we cloned and expressed the GRASP homolog from Leishmania. We found that Leishmania expresses one GRASP homolog of 58 kDa protein (LdGRASP) which localizes in LdRab1- and LPG2-positive Golgi compartment in Leishmania. LdGRASP was found to bind with COPII complex, LdARF1, LdRab1 and LdRab11 indicating its role in ER and Golgi transport in Leishmania. To determine the function of LdGRASP, we generated LdGRASP knockout parasites using CRISPR-Cas9. We found fragmentation of Golgi in Ld:GRASPKO parasites. Our results showed enhanced transport of non-GPI-anchored gp63 to the cell surface leading to higher secretion of this form of gp63 in Ld:GRASPKO parasites in comparison to Ld:WT cells. In contrast, we found that transport of GPI-anchored gp63 to the cell surface is blocked in Ld:GRASPKO parasites and thereby inhibits its secretion. The overexpression of dominant-negative mutant of LdRab1 or LdSar1 in Ld:GRASPKO parasites significantly blocked the secretion of non-GPI-anchored gp63. Interestingly, we found that survival of transgenic parasites overexpressing Ld:GRASP-GFP is significantly compromised in macrophages in comparison to Ld:WT and Ld:GRASPKO parasites. These results demonstrated that LdGRASP differentially regulates Ldgp63 secretory pathway in Leishmania.
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Affiliation(s)
- Kamal Kumar
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
| | - Rituparna Basak
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
| | - Aakansha Rai
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
| | - Amitabha Mukhopadhyay
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
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Transcriptomic expression of AMPA receptor subunits and their auxiliary proteins in the human brain. Neurosci Lett 2021; 755:135938. [PMID: 33915226 DOI: 10.1016/j.neulet.2021.135938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 11/21/2022]
Abstract
Receptors to glutamate of the AMPA type (AMPARs) serve as the major gates of excitation in the human brain, where they participate in fundamental processes underlying perception, cognition and movement. Due to their central role in brain function, dysregulation of these receptors has been implicated in neuropathological states associated with a large variety of diseases that manifest with abnormal behaviors. The participation of functional abnormalities of AMPARs in brain disorders is strongly supported by genomic, transcriptomic and proteomic studies. Most of these studies have focused on the expression and function of the subunits that make up the channel and define AMPARs (GRIA1-GRIA4), as well of some accessory proteins. However, it is increasingly evident that native AMPARs are composed of a complex array of accessory proteins that regulate their trafficking, localization, kinetics and pharmacology, and a better understanding of the diversity and regional expression of these accessory proteins is largely needed. In this review we will provide an update on the state of current knowledge of AMPA receptors subunits in the context of their accessory proteins at the transcriptome level. We also summarize the regional expression in the human brain and its correlation with the channel forming subunits. Finally, we discuss some of the current limitations of transcriptomic analysis and propose potential ways to overcome them.
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White JA, Krzystek TJ, Hoffmar-Glennon H, Thant C, Zimmerman K, Iacobucci G, Vail J, Thurston L, Rahman S, Gunawardena S. Excess Rab4 rescues synaptic and behavioral dysfunction caused by defective HTT-Rab4 axonal transport in Huntington's disease. Acta Neuropathol Commun 2020; 8:97. [PMID: 32611447 PMCID: PMC7331280 DOI: 10.1186/s40478-020-00964-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington's disease (HD) is characterized by protein inclusions and loss of striatal neurons which result from expanded CAG repeats in the poly-glutamine (polyQ) region of the huntingtin (HTT) gene. Both polyQ expansion and loss of HTT have been shown to cause axonal transport defects. While studies show that HTT is important for vesicular transport within axons, the cargo that HTT transports to/from synapses remain elusive. Here, we show that HTT is present with a class of Rab4-containing vesicles within axons in vivo. Reduction of HTT perturbs the bi-directional motility of Rab4, causing axonal and synaptic accumulations. In-vivo dual-color imaging reveal that HTT and Rab4 move together on a unique putative vesicle that may also contain synaptotagmin, synaptobrevin, and Rab11. The moving HTT-Rab4 vesicle uses kinesin-1 and dynein motors for its bi-directional movement within axons, as well as the accessory protein HIP1 (HTT-interacting protein 1). Pathogenic HTT disrupts the motility of HTT-Rab4 and results in larval locomotion defects, aberrant synaptic morphology, and decreased lifespan, which are rescued by excess Rab4. Consistent with these observations, Rab4 motility is perturbed in iNeurons derived from human Huntington's Disease (HD) patients, likely due to disrupted associations between the polyQ-HTT-Rab4 vesicle complex, accessory proteins, and molecular motors. Together, our observations suggest the existence of a putative moving HTT-Rab4 vesicle, and that the axonal motility of this vesicle is disrupted in HD causing synaptic and behavioral dysfunction. These data highlight Rab4 as a potential novel therapeutic target that could be explored for early intervention prior to neuronal loss and behavioral defects observed in HD.
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Affiliation(s)
- Joseph A. White
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Thomas J. Krzystek
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Hayley Hoffmar-Glennon
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Claire Thant
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Katherine Zimmerman
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Gary Iacobucci
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Julia Vail
- Department of Biological Engineering, Cornell University, Ithaca, NY USA
| | - Layne Thurston
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Saad Rahman
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, New York, 14260 USA
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Moretto E, Passafaro M. Recent Findings on AMPA Receptor Recycling. Front Cell Neurosci 2018; 12:286. [PMID: 30233324 PMCID: PMC6129582 DOI: 10.3389/fncel.2018.00286] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/10/2018] [Indexed: 02/04/2023] Open
Abstract
α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPA-Rs) are tetrameric protein complexes that mediate most of the fast-excitatory transmission in response to the neurotransmitter glutamate in neurons. The abundance of AMPA-Rs at the surface of excitatory synapses establishes the strength of the response to glutamate. It is thus evident that neurons need to tightly regulate this feature, particularly in the context of all synaptic plasticity events, which are considered the biological correlates of higher cognitive functions such as learning and memory. AMPA-R levels at the synapse are regulated by insertion of newly synthesized receptors, lateral diffusion on the plasma membrane and endosomal cycling. The latter is likely the most important especially for synaptic plasticity. This process starts with the endocytosis of the receptor from the cell surface and is followed by either degradation, if the receptor is directed to the lysosomal compartment, or reinsertion at the cell surface through a specialized endosomal compartment called recycling endosomes. Although the basic steps of this process have been discovered, the details and participation of additional regulatory proteins are still being discovered. In this review article, we describe the most recent findings shedding light on this crucial mechanism of synaptic regulation.
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Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
| | - Maria Passafaro
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
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Bourke AM, Bowen AB, Kennedy MJ. New approaches for solving old problems in neuronal protein trafficking. Mol Cell Neurosci 2018; 91:48-66. [PMID: 29649542 DOI: 10.1016/j.mcn.2018.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 11/16/2022] Open
Abstract
Fundamental cellular properties are determined by the repertoire and abundance of proteins displayed on the cell surface. As such, the trafficking mechanisms for establishing and maintaining the surface proteome must be tightly regulated for cells to respond appropriately to extracellular cues, yet plastic enough to adapt to ever-changing environments. Not only are the identity and abundance of surface proteins critical, but in many cases, their regulated spatial positioning within surface nanodomains can greatly impact their function. In the context of neuronal cell biology, surface levels and positioning of ion channels and neurotransmitter receptors play essential roles in establishing important properties, including cellular excitability and synaptic strength. Here we review our current understanding of the trafficking pathways that control the abundance and localization of proteins important for synaptic function and plasticity, as well as recent technological advances that are allowing the field to investigate protein trafficking with increasing spatiotemporal precision.
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Affiliation(s)
- Ashley M Bourke
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Aaron B Bowen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States.
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Zhou ZW, Yang QD, Tang QP, Yang J, Guo RJ, Jiang W. Effect of willed movement training on neurorehabilitation after focal cerebral ischemia and on the neural plasticity-associated signaling pathway. Mol Med Rep 2017; 17:1173-1181. [PMID: 29115485 DOI: 10.3892/mmr.2017.7964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 09/12/2017] [Indexed: 11/06/2022] Open
Abstract
Neurorehabilitation training is a therapeutic intervention for the loss of neural function induced by focal cerebral ischemia, however, the effect varies depending on the neurorehabilitation exercises. Willed movement (WM) training is defined as task‑oriented training, which increases enthusiasm of patients to accomplish a specific task. The current study was performed to the evaluate effect of WM training on neurorehabilitation following focal cerebral ischemia, and further investigate the influence on neural plasticity‑associated signaling pathway. Sprague‑Dawley rats following temporary middle cerebral artery occlusion (tMCAO) were randomly divided into four groups: tMCAO (no rehabilitation training), CR (control rehabilitation), EM (environmental modification) and WM groups. Rats in the CR group were forced to exercise (running) in a rotating wheel. In the WM group, food was used to entice rats to climb on a herringbone ladder. Herringbone ladders were also put into the cages of the rats in the CR and EM groups, however without the food attraction. WM group exhibited an improvement in neurobehavioral performance compared with other groups. TTC staining indicated an evident reduction in brain damage in the WM group. There were increased synaptic junctions following WM training, based on the observations of transmission election microscopy. Investigation of the molecular mechanism suggested that WM training conferred the greatest effect on stimulating the extracellular signal‑related kinase (ERK)/cyclic adenosine monophosphate response element‑binding protein 1 (CREB) pathway and glutamate receptor 2 (GluR2)/glutamate receptor interacting protein 1‑associated protein 1 (GRASP‑1)/protein interacting with C‑kinase 1 (PICK1) cascades among groups. Collectively, the improvement of neurobehavioral performance by WM training following tMCAO is suggested to involve the ERK/CREB pathway and GluR2/GRASP‑1/PICK1 cascades. The present study provided a preliminary foundation for future research on the therapeutic effect of WM training against stroke‑induced neuron damage.
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Affiliation(s)
- Zhi-Wen Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Qi-Dong Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Qing-Ping Tang
- Department of Physiology, School of Basic Medical Sciences, Central South University, Changsha, Hunan 410008, P.R. China
| | - Jie Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Rong-Jing Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Wen Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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Yap CC, Digilio L, McMahon L, Winckler B. The endosomal neuronal proteins Nsg1/NEEP21 and Nsg2/P19 are itinerant, not resident proteins of dendritic endosomes. Sci Rep 2017; 7:10481. [PMID: 28874679 PMCID: PMC5585371 DOI: 10.1038/s41598-017-07667-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/29/2017] [Indexed: 12/28/2022] Open
Abstract
Membrane traffic critically regulates most aspects of neuronal function. Neurons express many neuronal-specific proteins that regulate membrane traffic, including the poorly understood small transmembrane proteins neural-specific gene 1 and 2 (Nsg1/NEEP21 and Nsg2/P19). Nsg1 has been implicated in regulating endosomal recycling and sorting of several important neuronal receptors. Nsg2 is largely unstudied. At steady-state, Nsg1 and Nsg2 only partially co-localize with known endosomal compartments, and it was suggested that they mark a neuronal-specific endosome. Since Nsg1 localizes to and functions in the dendritic endosome, we set out to discover how Nsg1 and Nsg2 localization to endosomes is regulated in primary rat hippocampal neurons, using quadruple immunolocalization against endogenous proteins, live imaging of dendritic endosomes, and interference approaches against the endosomal regulators Rab5 and Rab7. In contrast to previous conclusions, we now show that Nsg1 and Nsg2 are not resident endosomal proteins, but traffic rapidly from the cell surface to lysosomes and have a half-life of less than two hours. Their partial co-localization with canonical endosomal markers thus reflects their rapid flux towards degradation rather than specific targeting to a singular compartment. These findings will require rethinking of how this class of endosomal proteins regulates trafficking of much longer-lived receptors.
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Affiliation(s)
- Chan Choo Yap
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Laura Digilio
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Lloyd McMahon
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA.
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Abstract
Synaptic connections in the brain are continuously weakened or strengthened in response to changes in neuronal activity. This process, known as synaptic plasticity, is the cellular basis for learning and memory, and is thought to be altered in several neuronal disorders. An important aspect of synaptic plasticity is the tightly controlled trafficking and synaptic targeting of the AMPA-type glutamate receptors, which are the major mediators of fast excitatory transmission in the brain. This review addresses the role of Rab GTPases in AMPA receptor trafficking in neurons under basal conditions and during activity-induced synaptic plasticity, especially during long-term potentiation (LTP) and long-term depression (LTD). We highlight the importance of the tight spatio-temporal control of Rab activity and suggest that this is critical for proper neuronal functions. We also discuss how abnormal AMPA receptor trafficking and malfunctioning of Rabs can lead to neurologic disorders or memory problems.
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Affiliation(s)
- Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart , Stuttgart , Germany.,Stuttgart Research Center Systems Biology, University of Stuttgart , Stuttgart , Germany
| | - Katalin Schlett
- Department of Physiology and Neurobiology, Eötvös Loránd University , Budapest , Hungary.,MTA-ELTE NAP B Neuronal Cell Biology Research Group, Eötvös Loránd University , Budapest , Hungary
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Abstract
Endosomes play critical roles on regulating surface receptor levels as well as signaling cascades in all cell types, including neurons. Endocytosis and endosomal trafficking is routinely studied after fixation, but live imaging is increasingly being used to capture the dynamic nature of endosomes and is allowing increasingly sophisticated glimpses into trafficking processes in live neurons. In this chapter, we describe the basics of neuronal primary cultures, methods for expressing fluorescent proteins, and live imaging of cargos and endosomal regulators.
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Affiliation(s)
| | - Bettina Winckler
- Department of Neuroscience, University of Virginia Medical School, Charlottesville, VA, USA
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Fraisier C, Koraka P, Belghazi M, Bakli M, Granjeaud S, Pophillat M, Lim SM, Osterhaus A, Martina B, Camoin L, Almeras L. Kinetic analysis of mouse brain proteome alterations following Chikungunya virus infection before and after appearance of clinical symptoms. PLoS One 2014; 9:e91397. [PMID: 24618821 PMCID: PMC3949995 DOI: 10.1371/journal.pone.0091397] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/10/2014] [Indexed: 01/13/2023] Open
Abstract
Recent outbreaks of Chikungunya virus (CHIKV) infection have been characterized by an increasing number of severe cases with atypical manifestations including neurological complications. In parallel, the risk map of CHIKV outbreaks has expanded because of improved vector competence. These features make CHIKV infection a major public health concern that requires a better understanding of the underlying physiopathological processes for the development of antiviral strategies to protect individuals from severe disease. To decipher the mechanisms of CHIKV infection in the nervous system, a kinetic analysis on the host proteome modifications in the brain of CHIKV-infected mice sampled before and after the onset of clinical symptoms was performed. The combination of 2D-DIGE and iTRAQ proteomic approaches, followed by mass spectrometry protein identification revealed 177 significantly differentially expressed proteins. This kinetic analysis revealed a dramatic down-regulation of proteins before the appearance of the clinical symptoms followed by the increased expression of most of these proteins in the acute symptomatic phase. Bioinformatic analyses of the protein datasets enabled the identification of the major biological processes that were altered during the time course of CHIKV infection, such as integrin signaling and cytoskeleton dynamics, endosome machinery and receptor recycling related to virus transport and synapse function, regulation of gene expression, and the ubiquitin-proteasome pathway. These results reveal the putative mechanisms associated with severe CHIKV infection-mediated neurological disease and highlight the potential markers or targets that can be used to develop diagnostic and/or antiviral tools.
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Affiliation(s)
- Christophe Fraisier
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Penelope Koraka
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Maya Belghazi
- Aix-Marseille Université, CNRS, CRN2M UMR 7286, Marseille, France
| | - Mahfoud Bakli
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Samuel Granjeaud
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Matthieu Pophillat
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Stephanie M. Lim
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Albert Osterhaus
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Byron Martina
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Luc Camoin
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Lionel Almeras
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
- Unité de recherche en biologie et épidémiologie parasitaires (URBEP), Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France
- * E-mail:
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New insights in endosomal dynamics and AMPA receptor trafficking. Semin Cell Dev Biol 2011; 22:499-505. [PMID: 21843653 DOI: 10.1016/j.semcdb.2011.06.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 12/15/2022]
Abstract
The trafficking mechanisms that control the density of synaptic AMPA-type glutamate receptors have received significant attention because of their importance for regulating excitatory synaptic transmission and synaptic plasticity in the hippocampus. AMPA receptors are synthesized in the neuronal cell body and reach their postsynaptic targets after a complex journey involving multiple transport steps along different cytoskeleton structures and through various stages of the endocytic pathway. Dendritic spines are important sites for AMPA receptor trafficking and contain the basic components of endosomal recycling. On induction of synaptic plasticity, internalized AMPA receptors undergo endosomal sorting and cycle through early endosomes and recycling endosomes back to the plasma membrane (model for long-term potentiation) or target for degradation to the lysosomes (model for long-term depression). Exciting new studies now provide insight in actin-mediated processes that controls endosomal tubule formation and receptor sorting. This review describes the path of AMPA receptor internalization up to sites of recycling and summarizes recent studies on actin-mediated endosomal receptor sorting.
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Hammond JC, McCullumsmith RE, Haroutunian V, Meador-Woodruff JH. Endosomal trafficking of AMPA receptors in frontal cortex of elderly patients with schizophrenia. Schizophr Res 2011; 130:260-5. [PMID: 21576009 PMCID: PMC3139693 DOI: 10.1016/j.schres.2011.04.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 04/25/2011] [Accepted: 04/26/2011] [Indexed: 01/08/2023]
Abstract
Several lines of evidence indicate altered trafficking of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors in schizophrenia. Previous reports have implicated alterations in the endosomal trafficking of AMPA receptors in this illness. We hypothesized that late endosome content of AMPA receptor subunits is altered in schizophrenia. Accordingly, we developed a technique to isolate and measure contents of late endosomes from postmortem human tissue. We found no changes in the expression of the AMPA subunits, GluR1-4, in late endosomes from the dorsolateral prefrontal cortex in schizophrenia. We also hypothesized that proteins involved in the sorting and trafficking of AMPA receptors between endosomal compartments would be altered in schizophrenia. We found no changes in expression of multiple proteins associated with these processes (dynamin3, Arc/ARG3.1, NEEP21, GRASP1, liprin α, and syntaxin13). Together, these data suggest that endosomal trafficking of AMPA receptors in the prefrontal cortex may be largely intact in schizophrenia.
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Affiliation(s)
- John C. Hammond
- Department of Neurobiology, University of Alabama Birmingham, Birmingham, AL,Department of Psychiatry and Behavioral Neurobiology, University of Alabama Birmingham, Birmingham, AL
| | - Robert E. McCullumsmith
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama Birmingham, Birmingham, AL
| | | | - James H. Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama Birmingham, Birmingham, AL
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