Related Experiment Video
Updated: Jul 19, 2026
09:14
Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
Published on: June 13, 2014
Membrane-proximal signaling events in beta-2 integrin activation
Bettina Kellersch1, Waldemar Kolanus
1Life and Medical Sciences Institute (LIMES), Molecular Immune and Cell Biology Program Unit, Laboratory of Molecular Immunology, University of Bonn, Germany.
Results and Problems in Cell Differentiation
|October 31, 2006
Summary
Leukocyte function-associated antigen-1 (LFA-1) is crucial for immune cell interactions and trafficking. Understanding its regulation by intracellular signaling proteins is key to controlling immune responses.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Integrins, such as leukocyte function-associated antigen-1 (LFA-1), are vital for immune cell functions including trafficking, adhesion, and extravasation.
- LFA-1, exclusively on hematopoietic cells, mediates critical interactions like T-cell antigen-presenting cell engagement and immune cell extravasation.
Purpose of the Study:
- To review recent developments in understanding the spatial and temporal control of LFA-1 interactions with intercellular adhesion molecules (ICAMs).
- To highlight transmembrane and intracellular signaling proteins involved in beta-2 integrin activation.
Main Methods:
- Literature review focusing on intracellular signaling pathways regulating LFA-1 adhesiveness.
- Identification of interaction partners of integrin alpha and beta subunits.
Main Results:
- LFA-1 activation is induced by extracellular stimuli, including T-cell receptor signaling, cytokines, chemokines, and lipopolysaccharide (LPS).
- Research has identified key transmembrane and intracellular signaling proteins that regulate LFA-1 activation.
Conclusions:
- A precise understanding of LFA-1 regulation is of high interest for various immune system functions.
- Recent advances in identifying intracellular signaling proteins provide insights into beta-2 integrin activation.
Related Concept Videos
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...
01:15Activation 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.
01:10Integrins
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,...
01:15Amplifying Signals via Second Messengers
Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
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,...
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...