Cellular Proteins in Influenza Virus Particles (original) (raw)
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The In Situ Structural Characterization of the Influenza A Virus Matrix M1 Protein within a Virion
Protein & Peptide Letters, 2009
The first attempt has been made to suggest a model of influenza A virus matrix M1 protein spatial structure and molecule orientation within a virion on the basis of tritium planigraphy data and theoretical prediction results. Limited in situ proteolysis of the intact virions with bromelain and surface plasmon resonance spectroscopy study of the M1 protein interaction with lipid coated surfaces were used for independent confirmation of the proposed model.
Journal of Virology, 2000
Influenza virus matrix protein (M1), a critical protein required for virus assembly and budding, is presumed to interact with viral glycoproteins on the outer side and viral ribonucleoprotein on the inner side. However, because of the inherent membrane-binding ability of M1 protein, it has been difficult to demonstrate the specific interaction of M1 protein with hemagglutinin (HA) or neuraminidase (NA), the influenza virus envelope glycoproteins. Using Triton X-100 (TX-100) detergent treatment of membrane fractions and floatation in sucrose gradients, we observed that the membrane-bound M1 protein expressed alone or coexpressed with heterologous Sendai virus F was totally TX-100 soluble but the membrane-bound M1 protein expressed in the presence of HA and NA was predominantly detergent resistant and floated to the top of the density gradient. Furthermore, both the cytoplasmic tail and the transmembrane domain of HA facilitated binding of M1 to detergent-resistant membranes. Analysis of the membrane association of M1 in the early and late phases of the influenza virus infectious cycle revealed that the interaction of M1 with mature glycoproteins which associated with the detergent-resistant lipid rafts was responsible for the detergent resistance of membrane-bound M1. Immunofluorescence analysis by confocal microscopy also demonstrated that, in influenza virus-infected cells, a fraction of M1 protein colocalized with HA and associated with the HA in transit to the plasma membrane via the exocytic pathway. Similar results for colocalization were obtained when M1 and HA were coexpressed and HA transport was blocked by monensin treatment. These studies indicate that both HA and NA interact with influenza virus M1 and that HA associates with M1 via its cytoplasmic tail and transmembrane domain.
Conserved and host-specific features of influenza virion architecture
Nature Communications, 2014
Viruses use virions to spread between hosts, and virion composition is therefore the primary determinant of viral transmissibility and immunogenicity. However, the virions of many viruses are complex and pleomorphic, making them difficult to analyse in detail. Here we address this by identifying and quantifying virion proteins with mass spectrometry, producing a complete and quantified model of the hundreds of host-encoded and viral proteins that make up the pleomorphic virions of influenza viruses. We show that a conserved influenza virion architecture is maintained across diverse combinations of virus and host. This 'core' architecture, which includes substantial quantities of host proteins as well as the viral protein NS1, is elaborated with abundant host-dependent features. As a result, influenza virions produced by mammalian and avian hosts have distinct protein compositions. Finally, we note that influenza virions share an underlying protein composition with exosomes, suggesting that influenza virions form by subverting microvesicle production.
Proteins of Influenza Virus: A Review
2013
Influenza virus infections are important both epidemically as well as pandemically and have great threat to avian species and humans especially, from last few decades. Certain pandemics of influenza virus have been reported causing severe damages. Once the host infected with influenza virus, it becomes immune-compromised and susceptible to secondary bacterial infections. Genome of influenza virus consists of eight segments of RNA, producing eleven types of proteins. Virulence and pathogenecity greatly depend upon its surface glycoproteins such as neuraminidase (NA) and hemagglutinin (HA). Other proteins of influenza virus are nucleoprotein (NP), 2 types of matrix proteins (M1 and M2), 2 non-structural proteins (NS1 and NS2), and polymerase subunit (PA) i.e. PB1, PB1-F2 and PB2. NP and M proteins are responsible for further classification of Influenza virus into influenza virus A, influenza virus B and influenza virus C. The aim of the review article is to discuss the structural importance of proteins of influenza A viruses. All copyrights reserved to Nexus® academic publishers
Journal of Virology, 2010
The matrix protein (M1) of influenza A virus is generally viewed as a key orchestrator in the release of influenza virions from the plasma membrane during infection. In contrast to this model, recent studies have indicated that influenza virus requires expression of the envelope proteins for budding of intracellular M1 into virus particles. Here we explored the mechanisms that control M1 budding. Similarly to previous studies, we found that M1 by itself fails to form virus-like-particles (VLPs). We further demonstrated that M1, in the absence of other viral proteins, was preferentially targeted to the nucleus/perinuclear region rather than to the plasma membrane, where influenza virions bud. Remarkably, we showed that a 10-residue membrane targeting peptide from either the Fyn or Lck oncoprotein appended to M1 at the N terminus redirected M1 to the plasma membrane and allowed M1 particle budding without additional viral envelope proteins. To further identify a functional link betwee...
Matrix proteins of enveloped viruses: a case study of Influenza A virus M1 protein
Journal of Biomolecular Structure and Dynamics, 2018
Influenza A virus, a member of the Orthomyxoviridae family of enveloped viruses, is one of the human and animal top killers, and its structure and components are therefore extensively studied during the last decades. The most abundant component, M1 matrix protein, forms a matrix layer (scaffold) under the viral lipid envelope, and the functional roles as well as structural peculiarities of the M1 protein are still under heavy debate. Despite multiple attempts of crystallization, no high resolution structure is available for the full length M1 of Influenza A virus. The likely reason for the difficulties lies in the intrinsic disorder of the M1 C-terminal part preventing diffraction quality crystals to be grown. Alternative structural methods including synchrotron small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), cryo-electron microscopy (CEM)/tomography (CET) are therefore widely applied to understand the structure of M1, its self-association and interactions with the lipid membrane and the viral nucleocapsid. These methods reveal striking similarities in the behaviour of M1 and matrix proteins of other enveloped RNA viruses, with the differences accompanied by the specific features of the viral lifecycles, thus suggesting common interaction principles and, possibly, common evolutional ancestors. The structural information on the Influenza A virus M1 protein obtained to the date strongly suggests that the intrinsic disorder in the C-terminal domain has important functional implications.
Membrane Interaction of Influenza Virus M1 Protein
Virology, 2000
The M1 protein of influenza virus is thought to make contact with the cytoplasmic tails of the glycoprotein spikes, lipid molecules in the viral membrane, and the internal ribonucleoprotein particles. Here we show electron micrographs of negatively stained virus particles in which M1 is visualized as a 60-Å-long rod that touches the membrane but apparently is not membrane inserted. Photolabeling with a membrane restricted reagent resulted in labeling of the transmembrane region of haemagglutinin but not of M1, also suggesting that most of M1 is not embedded into the hydrophobic core of the viral membrane. Finally, in vitro reconstitution experiments using soluble M1 protein and synthetic liposomes or Madin-Darby canine kidney cell membranes suggest that M1 can bind to negatively charged liposomes and to the cellular membranes and that this binding can be prevented under high-salt conditions. Although none of these experiments prove that there does not exist a minor fraction of M1 that is membrane inserted, it appears that most of M1 in the virus is membrane associated through electrostatic interactions.
PloS one, 2016
The influenza A(H1N1)pdm09 virus caused the first influenza pandemic of the 21st century. In this study, we wanted to decipher the role of conserved basic residues of the viral M1 matrix protein in virus assembly and release. M1 plays many roles in the influenza virus replication cycle. Specifically, it participates in viral particle assembly, can associate with the viral ribonucleoprotein complexes and can bind to the cell plasma membrane and/or the cytoplasmic tail of viral transmembrane proteins. M1 contains an N-terminal domain of 164 amino acids with two basic domains: the nuclear localization signal on helix 6 and an arginine triplet (R76/77/78) on helix 5. To investigate the role of these two M1 basic domains in influenza A(H1N1)pdm09 virus molecular assembly, we analyzed M1 attachment to membranes, virus-like particle (VLP) production and virus infectivity. In vitro, M1 binding to large unilamellar vesicles (LUVs), which contain negatively charged lipids, decreased significa...
Journal of virology, 1985
An investigation of properties of the influenza A virus M2 protein indicated that it is synthesized by 2 h postinfection together with other viral polypeptides and is transported to the infected-cell surface with a half-time of approximately 30 to 40 min. The available evidence suggests that M2 is not N-glycosylated even though it contains a potential glycosylation site, and the intracellular pattern of protein distribution includes localization to the Golgi apparatus. Proteolysis of intracellular microsome vesicles followed by immunoprecipitation with antiserum to a synthetic oligopeptide indicated that the M2 protein contains an extensive region of COOH-terminal amino acids exposed on the cytoplasmic side of the infected-cell membrane. A cDNA clone of the M2 mRNA was obtained and expressed in an SV40 recombinant vector. The M2 protein expressed by the vector became associated with the Golgi complex and was found on the surface of vector-infected cells. M2 is antigenically conserve...