Related Experiment Video
Updated: Jun 5, 2026
12:24
Helical Organization of Blood Coagulation Factor VIII on Lipid Nanotubes
Published on: June 3, 2014
Membrane-binding properties of the Factor VIII C2 domain
Valerie A Novakovic1, David B Cullinan, Hironao Wakabayashi
1Department of Medicine, Veterans Affairs Boston Healthcare System, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02132, USA.
The Biochemical Journal
|January 8, 2011
Summary
The isolated C2 domain of Factor VIII (fVIII-C2) shows significantly reduced membrane binding compared to intact Factor VIII. This suggests the C2 domain requires other Factor VIII domains for its characteristic membrane interactions.
Area of Science:
- Biochemistry
- Molecular Biology
- Hematology
Background:
- Factor VIII is a cofactor for Factor IXa, forming a membrane-bound complex that accelerates clotting activity.
- The C2 domain of Factor VIII is hypothesized to contain the primary phospholipid-binding motif responsible for membrane association.
- Understanding the specific role of the C2 domain in membrane binding is crucial for elucidating the full mechanism of Factor VIII function.
Purpose of the Study:
- To investigate the membrane-binding properties of the isolated Factor VIII C2 domain (fVIII-C2).
- To compare the membrane affinity and specificity of fVIII-C2 with intact Factor VIII.
- To determine if the C2 domain alone can recapitulate the functional membrane interactions of full-length Factor VIII.
Main Methods:
- Preparation of a recombinant fVIII-C2 construct using Escherichia coli expression.
- Confirmation of structural integrity of fVIII-C2 via monoclonal antibody binding assays.
- Solution-phase assays using flow cytometry and Förster resonance energy transfer (FRET) to measure membrane binding affinity and specificity.
Main Results:
- The isolated fVIII-C2 construct exhibited approximately 40-fold lower membrane affinity compared to intact Factor VIII.
- Unlike lactadherin's C2 domain, fVIII-C2 membrane binding was inhibited by physiological salt concentrations (NaCl).
- fVIII-C2 demonstrated non-specific binding to negatively charged phospholipids, whereas a Factor VIII construct lacking the C2 domain retained phosphatidylserine specificity.
Conclusions:
- The isolated C2 domain of Factor VIII does not replicate the characteristic high-affinity and specific membrane binding of the intact protein.
- The functional membrane interactions of the Factor VIII C2 domain appear to be dependent on cooperative effects with other domains within the full Factor VIII molecule.
- These findings highlight the importance of the complete protein structure for efficient and specific cofactor activity in the coagulation cascade.
Related Concept Videos
00:59Mechanisms of Membrane Domain Formation
Different physical properties of lipids and proteins allow them to localize and form distinct islands or domains in the membrane. Some membrane domains are formed due to protein-protein interactions, whereas others are formed due to the presence of specific lipids such as sphingolipids and sterols—for example, large proteins, such as bacteriorhodopsin, aggregate and create distinct domains.
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
01:18Membrane Domains
The membrane domains concentrate specific lipids and proteins at one place within the membrane, which helps in cell signaling, adhesion, and other critical cellular processes. These domains can differ in size, composition, function, and lifespan.
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the anterior...
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the anterior...
01:30Membrane Proteins
Plasma membranes have integral transmembrane proteins involved in facilitated transport. These proteins are collectively referred to as transport proteins, and they function as either channels for the material or as carriers themselves. Channel proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and a hydrophilic channel through their core that provides a hydrated opening for solutes to pass through the membrane layers. Passage through the channel allows...
01:30Membrane Proteins
Plasma membranes have integral transmembrane proteins involved in facilitated transport. These proteins are collectively referred to as transport proteins, and they function as either channels for the material or as carriers themselves. Channel proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and a hydrophilic channel through their core that provides a hydrated opening for solutes to pass through the membrane layers. Passage through the channel allows...
01:09Multi-pass Transmembrane Proteins and β-barrels
In multi-pass transmembrane proteins, the polypeptide chain crosses the membrane more than once. The transmembrane polypeptide chain either forms an α-helix or β-strand structure. α-Helix containing multi-pass transmembrane proteins are ubiquitous, whereas β-strand containing ones are mainly found in gram-negative bacteria, mitochondria, and chloroplasts.
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as G-protein-linked receptors (GPCRs) and...
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as G-protein-linked receptors (GPCRs) and...
01:49Conserved Binding Sites
Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...