Differential tyrosine phosphorylation of fibroblast growth factor (FGF) receptor-1 and receptor proximal signal transduction in response to FGF-2 and heparin.
The sulfated regions in heparan sulfate and heparin are known to affect fibroblast growth factor (FGF) function. We have studied the mechanism whereby heparin directs FGF-2-induced FGF receptor-1 (FGFR-1) signal transduction. FGF-2 alone stimulated maximal phosphorylation of Src homology domain 2 tyrosine phosphatase (SHP-2) and the adaptor molecule Crk, in heparan sulfate-deficient Chinese hamster ovary (CHO) 677 cells expressing FGFR-1. In contrast, for phospholipase Cgamma(1) (PLCgamma(1)) and the adaptor molecule Shb to be maximally tyrosine-phosphorylated, cells had to be stimulated with both FGF-2 and heparin (100 ng/ml). Tyrosine residues 463 in the juxtamembrane domain and 766 in the C-terminal tail in FGFR-1 are known to bind Crk and PLCgamma(1), respectively. Analysis of tryptic phosphopeptide maps of FGFR-1 from cells stimulated with FGF-2 alone and FGF-2 together with heparin showed that FGF-2 alone stimulated a several-fold increase in tyrosine 463 in the juxtamembrane domain. In contrast, heparin had to be included in order for tyrosine 766 to be phosphorylated to the same fold level. Our data imply that tyrosine 463 is phosphorylated and able to transduce signals in response to FGF-2 treatment alone; furthermore, we suggest that FGFR-1 dimerization/kinase activation is stabilized by heparin.
Lundin
Lars
L
Department of Genetics and Pathology, Uppsala University, The Rudbeck Laboratory, S-751 85, Uppsala, Sweden.
Rönnstrand
Lars
L
Cross
Michael
M
Hellberg
Carina
C
Lindahl
Ulf
U
Claesson-Welsh
Lena
L
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D005057:Eukaryotic Cells / Q000187:drug effects / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism* / Q000494:pharmacology; D006493:Heparin / Q000378:metabolism* / Q000494:pharmacology; D006497:Heparan Sulfate / Q000172:deficiency; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051966:Phospholipase C gamma; D010766:Phosphorylation / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects / Q000502:physiology; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000187:drug effects / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism; D050737:Proto-Oncogene Proteins c-crk; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D016222:Fibroblast Growth Factor 2; D006493:Heparin; D006497:Heparan Sulfate; D047908:Intracellular Signaling Peptides and Proteins; D051966:Phospholipase C gamma; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D011518:Proto-Oncogene Proteins; D050737:Proto-Oncogene Proteins c-crk; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor; D010738:Type C Phospholipases; D014443:Tyrosine; C490081:SHB protein, human; C496348:FGFR1 protein, human; C516724:PTPN11 protein, human