Tyrosine replacement in P-selectin glycoprotein ligand-1 affects distinct kinetic and mechanical properties of bonds with P- and L-selectin

Proc Natl Acad Sci U S A. 1999 Nov 23;96(24):13771-6. doi: 10.1073/pnas.96.24.13771.

Abstract

Selectins are adhesion molecules that initiate tethering and rolling of leukocytes on the vessel wall. Rolling requires rapid formation and breakage of selectin-ligand bonds that must have mechanical strength to resist premature dissociation by the forces applied in shear flow. P- and L-selectin bind to the N-terminal region of P-selectin glycoprotein ligand-1 (PSGL-1), a mucin on leukocytes. To define determinants on PSGL-1 that contribute to the kinetic and mechanical properties of bonds with selectins, we compared rolling of transfected preB cells expressing P- or L-selectin on transfected cell monolayers expressing wild-type PSGL-1 or PSGL-1 constructs with substitutions in targeted N-terminal residues. Rolling through P- or L-selectin required a Thr or Ser at a specific position on PSGL-1, the attachment site for an essential O-glycan, but required only one of three nearby Tyr residues, which are sites for Tyr-SO(3) formation. The adhesive strengths and numbers of cells rolling through P- or L-selectin were similar on wild-type PSGL-1 and on each of the three PSGL-1 constructs containing only a single Tyr. However, the cells rolled more irregularly on the single-Tyr forms of PSGL-1. Analysis of the lifetimes of transient tethers on limiting densities of PSGL-1 revealed that L-selectin dissociated faster from single-Tyr than wild-type PSGL-1 at all shears examined. In sharp contrast, P-selectin dissociated faster from single-Tyr than wild-type PSGL-1 at higher shear but not at lower shear. Thus, tyrosine replacements in PSGL-1 affect distinct kinetic and mechanical properties of bonds with P- and L-selectin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • B-Lymphocytes / cytology
  • B-Lymphocytes / metabolism
  • CHO Cells
  • Cricetinae
  • Gene Expression
  • Genetic Engineering
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Kinetics
  • L-Selectin / genetics
  • L-Selectin / metabolism*
  • Ligands
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Molecular Sequence Data
  • Mucins / genetics
  • Mucins / metabolism*
  • Mutagenesis, Site-Directed
  • P-Selectin / genetics
  • P-Selectin / metabolism*
  • Sequence Homology, Amino Acid
  • Tyrosine / genetics
  • Tyrosine / metabolism*

Substances

  • Ligands
  • Membrane Glycoproteins
  • Mucins
  • P-Selectin
  • P-selectin ligand protein
  • L-Selectin
  • Tyrosine