Related Experiment Video

Updated: Aug 4, 2026

Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes
09:35

Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes

Published on: February 9, 2009

The membrane (M1) protein of influenza virus occurs in two forms and is a phosphoprotein

A Gregoriades, T Christie, K Markarian

    Journal of Virology
    |January 1, 1984
    PubMed

    Insights

    Influenza virus matrix protein (M1) exists in two forms, both phosphorylated and found in virus particles. These M1 forms have similar peptide maps but differ slightly in phosphorylation, with one containing phosphothreonine.

    Area of Science:

    • Virology
    • Molecular Biology
    • Protein Chemistry

    Background:

    • Influenza virus matrix protein (M1) is crucial for viral structure and assembly.
    • Previous studies suggested M1 heterogeneity, but its nature remained unclear.

    Purpose of the Study:

    • To investigate the heterogeneity of the influenza virus M1 protein.
    • To characterize the different forms of M1 protein within influenza virus particles.
    • To analyze the phosphorylation status and peptide composition of M1 variants.

    Main Methods:

    • Polyacrylamide gel electrophoresis (PAGE) for protein separation.
    • Tryptic peptide mapping to assess protein similarity.
    • Phosphorylation analysis using radiolabeling.
    • Immunoprecipitation for detection of specific proteins.

    Main Results:

    • Influenza M1 protein exists as two distinct forms in virus particles, present throughout infection.
    • Both M1 forms are phosphorylated, with one containing phosphoserine and the other phosphoserine and phosphothreonine.
    • Tryptic peptide analysis revealed high similarity between the two M1 forms, with a potential minor proteolytic difference.
    • A third, unidentified phosphorylated surface protein was detected in virus particles.

    Conclusions:

    • The influenza virus M1 protein is heterogeneous, existing in at least two distinct, phosphorylated forms.
    • These M1 forms exhibit conserved peptide structures but differential phosphorylation patterns.
    • Further research is needed to identify the unknown phosphorylated surface protein.

    More Related Videos

    Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein09:39

    Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein

    Published on: April 21, 2015

    A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation07:53

    A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation

    Published on: January 9, 2019

    Related Concept Videos

    Fluid Mosaic Model01:34

    Fluid Mosaic Model

    The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of membranes and serves as a foundation for future membrane-related studies. The model depicts the structure of the plasma membrane with a variety of components, which include phospholipids, proteins, and carbohydrates. These integral molecules are loosely bound, defining the cell’s border and providing fluidity for optimal function.LipidsThe most...
    Leaky Scanning02:28

    Leaky Scanning

    During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
    Fluid Mosaic Model01:19

    Fluid Mosaic Model

    Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich with the analogy of...
    Phosphoinositides and PIPs01:42

    Phosphoinositides and PIPs

    Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
    Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
    Influenza01:27

    Influenza

    Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...
    Inhibitors Of Virion Release01:25

    Inhibitors Of Virion Release

    Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...