HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Tyrosine replacement of PSGL-1 reduces association kinetics with P- and L-selectin on the cell membrane.

Abstract
Binding of selectins to P-selectin glycoprotein ligand-1 (PSGL-1) mediates tethering and rolling of leukocytes on the endothelium during inflammation. Previous measurements obtained with a flow-chamber assay have shown that mutations of three tyrosines at the PSGL-1 N-terminus (Y46, Y48, and Y51) increase the reverse rates and their sensitivity to the force of bonds with P- and L-selectin. However, the effects of these mutations on the binding affinities and forward rates have not been studied. We quantified these effects by using an adhesion frequency assay to measure two-dimensional affinity and kinetic rates at zero force. Wild-type PSGL-1 has 2.2- to 8.5-fold higher binding affinities for P- and L-selectin than PSGL-1 mutants with two of three tyrosines substituted by phenylalanines, and 9.6- to 49-fold higher affinities than the PSGL-1 mutant with all three tyrosines replaced. In descending order, the affinity decreased from wild-type to Y48/51F, Y46/51F, Y46/48F, and Y46/48/51F. The affinity differences were attributed to major changes in the forward rate and minor changes in the reverse rate, suggesting that these tyrosines regulate the accessibility of PSGL-1 to P- and L-selectin via electrostatic interactions, which is supported by molecular-dynamics simulations. Our results provide insights into the structure-function relationship of receptor-ligand binding at a single-residue level.
AuthorsBotao Xiao, Chunfang Tong, Xiaoling Jia, Rui Guo, Shouqin Lü, Yan Zhang, Rodger P McEver, Cheng Zhu, Mian Long
JournalBiophysical journal (Biophys J) Vol. 103 Issue 4 Pg. 777-85 (Aug 22 2012) ISSN: 1542-0086 [Electronic] United States
PMID22947939 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
CopyrightCopyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Chemical References
  • Membrane Glycoproteins
  • P-Selectin
  • P-selectin ligand protein
  • L-Selectin
  • Tyrosine
Topics
  • Amino Acid Substitution
  • Animals
  • CHO Cells
  • Cell Membrane (metabolism)
  • Cricetinae
  • Cricetulus
  • Humans
  • Kinetics
  • L-Selectin (metabolism)
  • Membrane Glycoproteins (chemistry, genetics, metabolism)
  • Molecular Dynamics Simulation
  • P-Selectin (metabolism)
  • Protein Binding
  • Protein Structure, Tertiary
  • Static Electricity
  • Tyrosine

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: