Related Experiment Video

Updated: Oct 25, 2025

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers
11:45

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers

Published on: March 8, 2012

12.4K

Structural insight into host plasma membrane association and assembly of HIV-1 matrix protein

Halilibrahim Ciftci1,2,3, Hiroshi Tateishi1, Kotaro Koiwai4

  • 1Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.

Scientific Reports
|August 5, 2021
PubMed

Insights

Inositol hexaphosphate (IP6) binding to the MA domain of HIV-1 Pr55Gag is crucial for viral assembly. Structural studies reveal IP6

Area of Science:

  • Structural Biology
  • Virology
  • Biochemistry

Background:

  • Pr55Gag oligomerization is essential for HIV-1 late-stage replication.
  • Inositol hexaphosphate (IP6) binding to the MA domain is linked to Pr55Gag oligomerization, but its precise binding site and structural role are unclear.
  • Understanding this interaction is key to elucidating HIV-1 virion assembly.

Purpose of the Study:

  • To determine the high-resolution crystal structures of the MA domain in complex with IP6.
  • To identify the specific binding site and structural details of IP6-MA interaction.
  • To investigate the interplay of IP6 with PIP2 in the context of HIV-1 assembly.

Main Methods:

  • High-resolution X-ray crystallography of MA-IP6 complexes.
  • Differential Scanning Fluorimetry (DSF).
  • Cryo- and ambient-temperature X-ray crystallography.
  • Gaussian Network Model (GNM)-based transfer entropy calculations.

Main Results:

  • Three distinct high-resolution crystal structures reveal the binding mode of IP6 to the MA domain.
  • Key residues involved in IP6 binding were identified through DSF and crystallographic analysis.
  • IP6 and PIP2 bind to neighboring, non-exclusive sites within the MA domain's basic region (residues 18-33).

Conclusions:

  • IP6 binding to the MA domain is structurally characterized, revealing its interaction mode.
  • The non-exclusive binding of IP6 and PIP2 suggests a coordinated role in viral membrane localization.
  • A novel model for HIV-1 assembly is proposed, involving IP6 in coordinating MA and CA domain oligomerization during budding.

More Related Videos

Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle GUV Membranes08:21

Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle GUV Membranes

Published on: July 28, 2016

9.1K
Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging07:29

Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging

Published on: December 1, 2011

41.7K

Related Concept Videos

Protein Complex Assembly02:41

Protein Complex Assembly

Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types.  Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...
14.0K
Overview of Cell-Matrix Interactions01:24

Overview of Cell-Matrix Interactions

The extracellular matrix or ECM holds cells together to form a tissue and allows the cells within the tissue to communicate. ECM comprises proteins such as fibronectin, collagen, laminin, etc. The most abundant protein in this space is collagen. Collagen fibers are interwoven with carbohydrate-containing protein molecules called proteoglycans. ECM allows cell migration and provides a structural scaffold at cell adhesion that anchors the cell when the extracellular matrix proteins interact with...
8.1K
What are Membranes?01:24

What are Membranes?

A cell's plasma membrane demarcates the cell's borders and determines the nature of its interaction with the environment. Cells exclude certain substances, take in others, and excrete some others in controlled quantities. The plasma membrane must be flexible to allow certain cells, such as red and white blood cells, to change their shape while passing through narrow capillaries. These are the more obvious plasma membrane functions. In addition, the plasma membrane's surface carries...
16.6K
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...
14.2K
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
6.1K
Mechanisms of Membrane Domain Formation00:59

Mechanisms 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...
3.4K