Micromolar Ca2+ concentrations are essential for Mg2+-dependent binding of collagen by the integrin α2β1 in human platelets

被引:69
作者
Onley, DJ
Knight, CG
Tuckwell, DS
Barnes, MJ
Farndale, RW
机构
[1] Univ Cambridge, Dept Biochem, Cambridge CB2 1QW, England
[2] Univ Manchester, Sch Biol Sci, Manchester M13 9PT, Lancs, England
关键词
D O I
10.1074/jbc.M004111200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Integrin receptor alpha(2)beta(1) requires micromolar Ca2+ to bind to collagen and to the peptide GPC(GPP)(5)GFO-GER(GPP)(5)GPC (denoted GFOGER-GPP, where O represents hydroxyproline), which contains the minimum recognition sequence for the collagen-binding alpha(2) I-domain (Knight, C, G,, Morton, L, F,, Peachey, A. R,, Tuckwell, D. S,, Farndale, R, W,, and Barnes, M. J, (2000) J, Biol. Chem. 275, 35-40), Platelet adhesion to these ligands is completely dependent on alpha(2)beta(1) in the presence of 2 mM Mg2+. However, we show here that this interaction was abolished in the presence of 25 mu M EGTA. Adhesion of Glanzmann's thrombasthenic platelets, which lack the fibrinogen receptor alpha(IIb)beta(3), was also inhibited by micromolar EGTA. Mg2+-dependent adhesion of platelets was restored by the addition of 10 mu M Ca2+, but millimolar Ca2+ was inhibitory. Binding of isolated alpha(2)beta(1) to GFOGER-GPP was 70% inhibited by 50 mu M EGTA but, as with intact platelets, was fully restored by the addition of micromolar Ca2+. 2 mM Ca2+ did not inhibit binding of isolated alpha(2)beta(1) to collagen or to GFOGER-GPP, Binding of recombinant Lu, I-domain was not inhibited by EGTA, nor did millimolar Ca2+ inhibit binding. Our data suggest that high affinity Ca2+ binding to alpha(2)beta(1), outside the I-domain, is essential for adhesion to collagen, This is the first demonstration of a Ca2+ requirement in alpha(2)beta(1) function.
引用
收藏
页码:24560 / 24564
页数:5
相关论文
共 38 条
[11]   An allosteric Ca2+ binding site on the beta 3 integrins that regulates the dissociation rate for RGD ligands [J].
Hu, DD ;
Barbas, CF ;
Smith, JW .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1996, 271 (36) :21745-21751
[12]   CA2+ SUPPRESSES CELL-ADHESION TO OSTEOPONTIN BY ATTENUATING BINDING-AFFINITY FOR INTEGRIN ALPHA(V)BETA(3) [J].
HU, DD ;
HOYER, JR ;
SMITH, JW .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1995, 270 (17) :9917-9925
[13]  
Kehrel B, 1998, BLOOD, V91, P491
[14]   INTERACTION OF TYPE-IV COLLAGEN WITH THE ISOLATED INTEGRIN-ALPHA-1-BETA-1 AND INTEGRIN-ALPHA-2-BETA-1 [J].
KERN, A ;
EBLE, J ;
GOLBIK, R ;
KUHN, K .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1993, 215 (01) :151-159
[15]   Collagen-platelet interaction: Gly-Pro-Hyp is uniquely specific for platelet Gp VI and mediates platelet activation by collagen [J].
Knight, CG ;
Morton, LF ;
Onley, DJ ;
Peachey, AR ;
Ichinohe, T ;
Okuma, M ;
Farndale, RW ;
Barnes, MJ .
CARDIOVASCULAR RESEARCH, 1999, 41 (02) :450-457
[16]   The collagen-binding A-domains of integrins α1β1 and α2β1 recognize the same specific amino acid sequence, GFOGER, in native (triple-helical) collagens [J].
Knight, CG ;
Morton, LF ;
Peachey, AR ;
Tuckwell, DS ;
Farndale, RW ;
Barnes, MJ .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (01) :35-40
[17]   Identification in collagen type I of an integrin α2β1-binding site containing an essential GER sequence [J].
Knight, CG ;
Morton, LF ;
Onley, DJ ;
Peachey, AR ;
Messent, AJ ;
Smethurst, PA ;
Tuckwell, DS ;
Farndale, RW ;
Barnes, MJ .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1998, 273 (50) :33287-33294
[18]  
Kuhn K, 1994, Trends Cell Biol, V4, P256, DOI 10.1016/0962-8924(94)90124-4
[19]   CRYSTAL-STRUCTURE OF THE A-DOMAIN FROM THE A-SUBUNIT OF INTEGRIN CR3 (CD11B/CD18) [J].
LEE, JO ;
RIEU, P ;
ARNAOUT, MA ;
LIDDINGTON, R .
CELL, 1995, 80 (04) :631-638
[20]  
Messent AJ, 1998, J CELL SCI, V111, P1127