Related Experiment Video
Updated: Aug 3, 2026
10:50
Nanopodia - Thin, Fragile Membrane Projections with Roles in Cell Movement and Intercellular Interactions
Published on: April 3, 2014
Selective tetraspan-integrin complexes (CD81/alpha4beta1, CD151/alpha3beta1, CD151/alpha6beta1) under conditions
V Serru1, F Le Naour, M Billard
1INSERM U268, Hôpital Paul Brousse, 94807 Villejuif Cedex, France.
The Biochemical Journal
|May 7, 1999
Summary
Tetraspans form molecular complexes with integrins. CD81 and CD151 directly bind specific beta1 integrins, while other tetraspans likely interact indirectly via CD81 or CD151.
Area of Science:
- Cellular biology
- Molecular interactions
- Protein complexes
Background:
- Tetraspans are transmembrane proteins involved in forming the 'tetraspan web'.
- This web includes beta1 integrins, MHC antigens, and other molecules.
- Mild detergents like Brij 97 or CHAPS facilitate detection of these tetraspan-associated molecules.
Purpose of the Study:
- To investigate the specific interactions between tetraspans and beta1 integrins.
- To determine which tetraspans form stable complexes with integrins.
- To elucidate the nature of tetraspan-integrin interactions within the tetraspan web.
Main Methods:
- Immunoprecipitation using mild detergents (digitonin, Brij 97, CHAPS).
- Analysis of molecular complexes formed by various tetraspans (CD9, CD37, CD53, CD63, CD82, Co-029, Talla-1, NAG-2, CD81, CD151) and beta1 integrins (alpha3beta1, alpha4beta1, alpha6beta1).
- Characterization of a novel anti-CD151 monoclonal antibody (mAb) TS151r and its binding affinity in relation to integrin expression.
Main Results:
- Digitonin disrupted most tetraspan-integrin complexes, except for those involving CD81 and CD151.
- CD81 formed stable complexes with alpha4beta1 integrin.
- CD151 formed stable complexes with alpha3beta1 and alpha6beta1 integrins, and its epitope was masked by integrin association.
Conclusions:
- CD81 directly interacts with alpha4beta1 integrin.
- CD151 directly interacts with alpha3beta1 and alpha6beta1 integrins.
- Other tetraspans likely associate indirectly with integrins through CD81 or CD151, as tetraspan-tetraspan interactions are disrupted by digitonin.
Related Concept Videos
01:30Assembly 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,...
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...
01:29Tight Junctions
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...
01:25Selectins
Cell adhesion is an essential aspect of multicellularity. While stable cell interactions usually occur between cells of the same type, transient cell interactions occur between cells of different tissue types, such as between neutrophils and endothelial cells. Selectins are one class of cell adhesion molecules (CAMs) that bind carbohydrate ligands to form transient cell adhesion. They are rod-like proteins with a long extracellular part of variable length ending with the lectin domain, which...