Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Structure-function of the putative I-domain within the integrin beta 2 subunit.

Y M Xiong1, L Zhang

  • 1Department of Vascular Biology, American Red Cross Holland Laboratory, Rockville, Maryland 20855, USA.

The Journal of Biological Chemistry
|March 30, 2001
PubMed
Summary

This study reveals that specific regions of the integrin beta(2) subunit are not critical for heterodimer formation but are essential for calcium binding and receptor conformation. Function-blocking antibodies inhibit alpha(M)beta(2) activity allosterically, differing from beta(3) integrin mechanisms.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Biological characterization of nef in long-term survivors of human immunodeficiency virus type 1 infection.

Journal of virology·1995
Same author

Virulence characteristics of Escherichia coli causing first urinary tract infection predict risk of second infection.

The Journal of infectious diseases·1995
Same author

Concordant loss of imprinting of the human insulin-like growth factor II gene promoters in cancer.

The Journal of biological chemistry·1995
Same author

Altered cAMP levels in retinas from transgenic mice expressing a rhodopsin mutant.

Biochemical and biophysical research communications·1995
Same author

Repetitive Ser-Gly sequences enhance heparan sulfate assembly in proteoglycans.

The Journal of biological chemistry·1995
Same author

The angiotensin II type 2 (AT2) receptor antagonizes the growth effects of the AT1 receptor: gain-of-function study using gene transfer.

Proceedings of the National Academy of Sciences of the United States of America·1995

Area of Science:

  • Integrin structure and function
  • Molecular cell biology
  • Immunology

Background:

  • The integrin beta(2) subunit's central region (beta(2)I-domain) is crucial for ligand binding and heterodimer formation.
  • Understanding its structure-function relationship is key to integrin-mediated cellular processes.

Purpose of the Study:

  • To investigate the role of specific sequences within the beta(2)I-domain in alpha(M)beta(2) integrin function.
  • To map antibody epitopes and elucidate the mechanism of ligand binding and inhibition.

Main Methods:

  • Homolog-scanning mutagenesis by substituting beta(2) sequences with beta(1) counterparts.
  • Transfection of mutant beta(2) subunits with wild-type alpha(M) in human 293 cells.
  • Epitope mapping using function-blocking monoclonal antibodies (mAbs).

Related Experiment Videos

Main Results:

  • 16 mutated beta(2) subunits formed heterodimers with alpha(M), indicating these regions aren't essential for complex formation.
  • Epitope mapping revealed mAb binding sites require noncontiguous segments, supporting an I-domain-like fold.
  • Mutations affecting mAb epitopes did not abolish ligand binding, suggesting allosteric inhibition by function-blocking mAbs.
  • Ligand binding mechanisms differ between beta(2) and beta(3) integrins.
  • A high-affinity Ca(2+) binding site within the beta(2)I-domain is critical for alpha(M)beta(2) conformation and C3bi binding.

Conclusions:

  • The beta(2)I-domain's outer surface sequences are not critical for alpha(M)beta(2) heterodimerization.
  • Function-blocking mAbs likely inhibit alpha(M)beta(2) via allosteric mechanisms.
  • Beta(2) integrin ligand binding differs from beta(3) integrins, with a critical calcium-binding site in the beta(2)I-domain.