Requirement for the Synergy Site for Cell Adhesion to Fibronectin Depends on the Activation State of Integrin α5β1 (*)
- Erik H. J. Danen(1)(§),
- Shin-ichi Aota(2),
- Annemieke A. van Kraats(1),
- Kenneth M. Yamada(2),
- Dirk J. Ruiter(1) and
- Goos N. P. van Muijen(1)
- From the (1) Department of Pathology, University Hospital, 6500 HB Nijmegen, The Netherlands and the
- (2) Laboratory of Developmental Biology, NIDR, National Institutes of Health, Bethesda, Maryland 20892
- §To whom correspondence should be addressed: Dept. of Pathology, University of Nijmegen, P. O. Box 9101, 6500 HB Nijmegen, The Netherlands. Fax: 31-80-540520.
Abstract
We investigated the influence of the activation state of integrin α5β1 on its dependence on the PHSRN synergy site for binding
to RGD in fibronectin. K562 and MV3 cells lacked αvβ3 expression and adhered to fibronectin through α5β1. Mel57 cells adhered
through αvβ3 and α5β1. A recombinant fibronectin polypeptide, containing five type III repeats from the central cell binding
domain 3Fn6-10, and a mutated polypeptide lacking the synergy site were equally effective in promoting Mel57 adhesion. For
K562 and MV3, the mutated polypeptide was not or poorly active compared to the control polypeptide. Expression of αvβ3 in
MV3 induced strong adhesion to the mutated polypeptide. TS2/16 stimulatory β1-integrin antibodies or Mn
induced α5β1-mediated adhesion of K562 and MV3 to GRGDSP. In the presence of TS2/16 or Mn
, α5β1-mediated MV3 adhesion to the mutated polypeptide was equally strong as adhesion to the control polypeptide. Mn
or TS2/16 induced weak K562 binding to the mutated polypeptide, and in the presence of a combination of phorbol 12-myristate
13-acetate, Mn
, and TS2/16, α5β1-mediated K562 adhesion to the mutated and control polypeptide was equally strong. Our findings demonstrate
that requirement for the PHSRN synergy site for α5β1-mediated adhesion to RGD in fibronectin depends on the activation state
of the integrin.
Footnotes
-
↵* This work was supported by Dutch Cancer Society Grant NUKC 91-09. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- Fn
-
fibronectin
- BSA
-
bovine serum albumin
- CCBD
-
central cell binding domain
- 3Fn10
-
10th type III fibronectin repeat
- mAb
-
monoclonal antibody
- PMA
-
phorbol 12-myristate 13-acetate
- DMEM
-
Dulbecco's modified Eagle's medium.
-
- Received April 5, 1995.
- Revision received July 11, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
