Related Experiment Video
Updated: Aug 13, 2026
09:14
Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
Published on: June 13, 2014
Junctional adhesion molecule-A-induced endothelial cell migration on vitronectin is integrin alpha v beta 3 specific
1Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA. unaik@udel.edu
Journal of Cell Science
|January 19, 2006
Summary
Junctional adhesion molecule-A (JAM-A) enhances human umbilical vein endothelial cell (HUVEC) migration on vitronectin by interacting with integrin alpha(v)beta(3). This signaling pathway involves phosphoinositide 3-kinase and protein kinase C, impacting vascular function.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Junctional adhesion molecule-A (JAM-A) is an immunoglobulin superfamily member found in epithelial and endothelial cell tight junctions.
- Previous research indicated JAM-A's role in basic fibroblast growth factor (bFGF)-induced angiogenesis.
Purpose of the Study:
- To investigate the role of JAM-A in endothelial cell migration on specific extracellular matrix proteins.
- To elucidate the molecular mechanisms by which JAM-A influences cell migration and associated signaling pathways.
Main Methods:
- Ectopic expression of JAM-A and a cytoplasmic domain deletion mutant in human umbilical vein endothelial cells (HUVECs).
- Cell migration assays on vitronectin and fibronectin using blocking antibodies for integrins.
- Inhibition studies using kinase inhibitors (PI3K, PKC) and anti-JAM-A antibodies.
- Co-immunoprecipitation to assess JAM-A and integrin alpha(v)beta(3) interaction.
- Western blot analysis for focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) activation.
Main Results:
- Ectopic JAM-A expression enhanced HUVEC migration specifically on vitronectin, mediated by integrin alpha(v)beta(3).
- JAM-A interacted with integrin alpha(v)beta(3), and this interaction was increased by RGDS peptide.
- JAM-A-induced migration required its cytoplasmic domain and involved phosphoinositide 3-kinase and protein kinase C signaling.
- JAM-A overexpression upregulated FAK and MAPK activation on vitronectin.
Conclusions:
- JAM-A signaling is essential for alpha(v)beta(3)-dependent HUVEC migration on vitronectin.
- JAM-A plays a significant role in regulating vascular cell migration and potentially vascular function.
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...
01:31Immunoglobulin-like Cell Adhesion Molecules
Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
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.
01:24Regulation of Angiogenesis and Blood Supply
Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits. Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...
01:24Adherens Junctions
Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types – adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
The endothelial cells...
Adherens Junctions are Dynamic
The endothelial cells...