A NPxY-independent β5 integrin activation signal regulates phagocytosis of apoptotic cells

Sukhwinder Singh, Veera D'mello, Paul van Bergen en Henegouwen, Raymond Birge

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Integrin receptors are heterodimeric transmembrane receptors with critical functions in cell adhesion and migration, cell cycle progression, differentiation, apoptosis, and phagocytosis of apoptotic cells. Integrins are activated by intracellular signaling that alter the binding affinity for extracellular ligands, so-called inside to outside signaling. A common element for integrin activation involves binding of the cytoskeletal protein talin, via its FERM domain, to a highly conserved NPxY motif in the β chain cytoplasmic tails, which is involved in long-range conformation changes to the extracellular domain that impinges on ligand affinity. When the human beta-5 (β5) integrin cDNA was expressed in αv positive, β5 and β3 negative hamster CS-1 cells, it promoted NPxY-dependent adhesion to VTN-coated surfaces, phosphorylation of FAK, and concomitantly, β5 integrin-EGFP protein was recruited into talin and paxillin-containing focal adhesions. Expression of a NPxY destabilizing β5 mutant (Y750A) abrogated adhesion and β5-Y750A-EGFP was excluded from focal adhesions at the tips of stress fibers. Surprisingly, expression of β5 Y750A integrin had a potent gain-of-function effect on apoptotic cell phagocytosis, and further, a β5-Y750A-EGFP fusion integrin readily bound MFG-E8-coated 10 μm diameter microspheres developed as apoptotic cell mimetics. The critical sequences in β5 integrin were mapped to a YEMAS motif just proximal to the NPxY motif. Our studies suggest that the phagocytic function of β5 integrin is regulated by an unconventional NPxY-talin-independent activation signal and argue for the existence of molecular switches in the β5 cytoplasmic tail for adhesion and phagocytosis.

Original languageEnglish (US)
Pages (from-to)540-548
Number of pages9
JournalBiochemical and Biophysical Research Communications
Volume364
Issue number3
DOIs
StatePublished - Dec 21 2007

Fingerprint

Cytophagocytosis
Integrins
Chemical activation
Cells
Talin
Adhesion
Focal Adhesions
Tail
Paxillin
Ligands
Stress Fibers
Phosphorylation
Cytoskeletal Proteins
Cell adhesion
Microspheres
Phagocytosis
Cell Adhesion
Cricetinae
Cell Movement
Conformations

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Singh, Sukhwinder ; D'mello, Veera ; Henegouwen, Paul van Bergen en ; Birge, Raymond. / A NPxY-independent β5 integrin activation signal regulates phagocytosis of apoptotic cells. In: Biochemical and Biophysical Research Communications. 2007 ; Vol. 364, No. 3. pp. 540-548.
@article{18e829b5db1b414fa3fe787bb2f06607,
title = "A NPxY-independent β5 integrin activation signal regulates phagocytosis of apoptotic cells",
abstract = "Integrin receptors are heterodimeric transmembrane receptors with critical functions in cell adhesion and migration, cell cycle progression, differentiation, apoptosis, and phagocytosis of apoptotic cells. Integrins are activated by intracellular signaling that alter the binding affinity for extracellular ligands, so-called inside to outside signaling. A common element for integrin activation involves binding of the cytoskeletal protein talin, via its FERM domain, to a highly conserved NPxY motif in the β chain cytoplasmic tails, which is involved in long-range conformation changes to the extracellular domain that impinges on ligand affinity. When the human beta-5 (β5) integrin cDNA was expressed in αv positive, β5 and β3 negative hamster CS-1 cells, it promoted NPxY-dependent adhesion to VTN-coated surfaces, phosphorylation of FAK, and concomitantly, β5 integrin-EGFP protein was recruited into talin and paxillin-containing focal adhesions. Expression of a NPxY destabilizing β5 mutant (Y750A) abrogated adhesion and β5-Y750A-EGFP was excluded from focal adhesions at the tips of stress fibers. Surprisingly, expression of β5 Y750A integrin had a potent gain-of-function effect on apoptotic cell phagocytosis, and further, a β5-Y750A-EGFP fusion integrin readily bound MFG-E8-coated 10 μm diameter microspheres developed as apoptotic cell mimetics. The critical sequences in β5 integrin were mapped to a YEMAS motif just proximal to the NPxY motif. Our studies suggest that the phagocytic function of β5 integrin is regulated by an unconventional NPxY-talin-independent activation signal and argue for the existence of molecular switches in the β5 cytoplasmic tail for adhesion and phagocytosis.",
author = "Sukhwinder Singh and Veera D'mello and Henegouwen, {Paul van Bergen en} and Raymond Birge",
year = "2007",
month = "12",
day = "21",
doi = "10.1016/j.bbrc.2007.10.049",
language = "English (US)",
volume = "364",
pages = "540--548",
journal = "Biochemical and Biophysical Research Communications",
issn = "0006-291X",
publisher = "Academic Press Inc.",
number = "3",

}

A NPxY-independent β5 integrin activation signal regulates phagocytosis of apoptotic cells. / Singh, Sukhwinder; D'mello, Veera; Henegouwen, Paul van Bergen en; Birge, Raymond.

In: Biochemical and Biophysical Research Communications, Vol. 364, No. 3, 21.12.2007, p. 540-548.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A NPxY-independent β5 integrin activation signal regulates phagocytosis of apoptotic cells

AU - Singh, Sukhwinder

AU - D'mello, Veera

AU - Henegouwen, Paul van Bergen en

AU - Birge, Raymond

PY - 2007/12/21

Y1 - 2007/12/21

N2 - Integrin receptors are heterodimeric transmembrane receptors with critical functions in cell adhesion and migration, cell cycle progression, differentiation, apoptosis, and phagocytosis of apoptotic cells. Integrins are activated by intracellular signaling that alter the binding affinity for extracellular ligands, so-called inside to outside signaling. A common element for integrin activation involves binding of the cytoskeletal protein talin, via its FERM domain, to a highly conserved NPxY motif in the β chain cytoplasmic tails, which is involved in long-range conformation changes to the extracellular domain that impinges on ligand affinity. When the human beta-5 (β5) integrin cDNA was expressed in αv positive, β5 and β3 negative hamster CS-1 cells, it promoted NPxY-dependent adhesion to VTN-coated surfaces, phosphorylation of FAK, and concomitantly, β5 integrin-EGFP protein was recruited into talin and paxillin-containing focal adhesions. Expression of a NPxY destabilizing β5 mutant (Y750A) abrogated adhesion and β5-Y750A-EGFP was excluded from focal adhesions at the tips of stress fibers. Surprisingly, expression of β5 Y750A integrin had a potent gain-of-function effect on apoptotic cell phagocytosis, and further, a β5-Y750A-EGFP fusion integrin readily bound MFG-E8-coated 10 μm diameter microspheres developed as apoptotic cell mimetics. The critical sequences in β5 integrin were mapped to a YEMAS motif just proximal to the NPxY motif. Our studies suggest that the phagocytic function of β5 integrin is regulated by an unconventional NPxY-talin-independent activation signal and argue for the existence of molecular switches in the β5 cytoplasmic tail for adhesion and phagocytosis.

AB - Integrin receptors are heterodimeric transmembrane receptors with critical functions in cell adhesion and migration, cell cycle progression, differentiation, apoptosis, and phagocytosis of apoptotic cells. Integrins are activated by intracellular signaling that alter the binding affinity for extracellular ligands, so-called inside to outside signaling. A common element for integrin activation involves binding of the cytoskeletal protein talin, via its FERM domain, to a highly conserved NPxY motif in the β chain cytoplasmic tails, which is involved in long-range conformation changes to the extracellular domain that impinges on ligand affinity. When the human beta-5 (β5) integrin cDNA was expressed in αv positive, β5 and β3 negative hamster CS-1 cells, it promoted NPxY-dependent adhesion to VTN-coated surfaces, phosphorylation of FAK, and concomitantly, β5 integrin-EGFP protein was recruited into talin and paxillin-containing focal adhesions. Expression of a NPxY destabilizing β5 mutant (Y750A) abrogated adhesion and β5-Y750A-EGFP was excluded from focal adhesions at the tips of stress fibers. Surprisingly, expression of β5 Y750A integrin had a potent gain-of-function effect on apoptotic cell phagocytosis, and further, a β5-Y750A-EGFP fusion integrin readily bound MFG-E8-coated 10 μm diameter microspheres developed as apoptotic cell mimetics. The critical sequences in β5 integrin were mapped to a YEMAS motif just proximal to the NPxY motif. Our studies suggest that the phagocytic function of β5 integrin is regulated by an unconventional NPxY-talin-independent activation signal and argue for the existence of molecular switches in the β5 cytoplasmic tail for adhesion and phagocytosis.

UR - http://www.scopus.com/inward/record.url?scp=35648951623&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35648951623&partnerID=8YFLogxK

U2 - 10.1016/j.bbrc.2007.10.049

DO - 10.1016/j.bbrc.2007.10.049

M3 - Article

VL - 364

SP - 540

EP - 548

JO - Biochemical and Biophysical Research Communications

JF - Biochemical and Biophysical Research Communications

SN - 0006-291X

IS - 3

ER -