Related Experiment Video

Updated: Aug 8, 2026

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
09:14

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes

Published on: June 13, 2014

Cytoplasmic tails of beta 1, beta 2, and beta 7 integrins differentially regulate LFA-1 function in K562 cells

M Lub1, S J van Vliet, S P Oomen

  • 1Department of Tumor Immunology, University Hospital Nijmegen St. Radboud, The Netherlands.

Molecular Biology of the Cell
|April 1, 1997
PubMed

Insights

Lymphocyte function-associated antigen 1 (LFA-1) requires specific cellular elements for activation. Replacing the LFA-1 beta 2 cytoplasmic tail with beta 1 restores activation, indicating distinct signaling pathways for integrin activation.

Area of Science:

  • Cellular Biology
  • Immunology
  • Molecular Biology

Background:

  • Lymphocyte function-associated antigen 1 (LFA-1), a beta 2 integrin, mediates lymphocyte adhesion.
  • LFA-1 activation is crucial for immune cell interactions.
  • The role of lymphocyte-specific elements in LFA-1 function remains unclear.

Purpose of the Study:

  • To investigate the necessity of lymphocyte-specific elements for LFA-1 function.
  • To determine the role of the cytoplasmic domain of beta subunits in regulating LFA-1 activation.
  • To elucidate the signaling pathways governing beta 1 and beta 2 integrin activation.

Main Methods:

  • Expression of LFA-1 in the K562 erythroleukemic cell line.
  • Stimulation with phorbol 12-myristate 13-acetate (PMA) and LFA-1-activating antibody KIM185.
  • Transfection of chimeric LFA-1 receptors with swapped cytoplasmic tails (beta 1, beta 7).
  • Analysis of LFA-1 localization and clustering.

Main Results:

  • LFA-1-expressing K562 cells showed no PMA-induced adhesion to intercellular adhesion molecule 1 (ICAM-1), but KIM185 enhanced adhesion.
  • Replacement of the beta 2 cytoplasmic tail with the beta 1 tail restored PMA responsiveness.
  • A beta 2 cytoplasmic deletion mutant was constitutively active.
  • Altering the beta 2 cytoplasmic tail affected LFA-1 localization and clustering, regulating adhesion.

Conclusions:

  • Distinct signaling pathways activate beta 1 and beta 2 integrins via their respective beta-chains.
  • Lymphocyte-specific signal transduction elements are likely involved in beta 2 and beta 7 integrin activation.
  • These elements appear to be absent in the non-lymphocytic K562 cell line.

More Related Videos

Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions07:40

Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions

Published on: June 29, 2016

A Flow Cytometry-Based High-Throughput Technique for Screening Integrin-Inhibitory Drugs04:15

A Flow Cytometry-Based High-Throughput Technique for Screening Integrin-Inhibitory Drugs

Published on: February 2, 2024

Related Concept Videos

Fibronectins Connect Cells with ECM01:25

Fibronectins Connect Cells with ECM

Fibronectin is an adhesive glycoprotein present in the extracellular matrix of embryogenic and adult tissue. These molecules primarily aid in regulating cell motility and attachment. A fibronectin molecule is composed of two identical polypeptide chains attached to each other by a pair of disulfide bonds at the C-terminal.
Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane...
Integrins01:10

Integrins

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,...
Activation of Integrins01:15

Activation 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.
Intracellular Signaling Affects Focal Adhesions01:17

Intracellular 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...
Selectins01:25

Selectins

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...
Immunoglobulin-like Cell Adhesion Molecules01:31

Immunoglobulin-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...