Human SPRY2 inhibits FGF2 signalling by a secreted factor.
Growth factor signalling pathways and their inhibitors coordinate the formation of three-dimensional patterns of vertebrates and invertebrates. Temporal and spatial restriction of the response to a few well-defined cells is crucial and needs the integration of positive and negative signals. Recently, Spry has been identified as an inhibitor of fibroblast growth factor (FGF) signalling during Drosophila trachea development. Spry has been described as an intracellular protein that can exert its function in a cell autonomous or a paracrine manner. Here we describe the role of SPRY2, a human homologue of Spry, in human FGF2 signalling. We show that in primary human dermal endothelial cells (MVEC) SPRY2 mRNA is transiently upregulated in response to FGF2. Overexpression of SPRY2 in A375 cells leads to the secretion of a soluble factor that inhibits FGF2- but not VEGF-stimulated proliferation of MVEC. Direct administration of recombinant SPRY2 protein has no effect on MVEC proliferation. However, SPRY2 protein binds the intracellular adaptor protein GRB2, indicating an intracellular localization. A SPRY2/GFP fusion protein remains in the cell, further supporting the intracellular localization of SPRY2. So the intracellular protein SPRY2 is involved in the non-cell autonomous inhibitory effect indirectly, via regulating the secretion of an inhibitor of FGF2 signalling in vertebrates, the evidence of which is presented here for the first time.
Glienke
J
J
Research Laboratories, Schering AG, Experimental Oncology, Müllerstrasse 178, D-13342, Berlin, Germany.
Fenten
G
G
Seemann
M
M
Sturz
A
A
Thierauch
K H
KH
D048868:Adaptor Proteins, Signal Transducing; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D016228:Endothelial Growth Factors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000235:genetics* / Q000378:metabolism*; D051380:GRB2 Adaptor Protein; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D008565:Membrane Proteins; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000096:biosynthesis; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D048868:Adaptor Proteins, Signal Transducing; D016228:Endothelial Growth Factors; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D008222:Lymphokines; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C485561:SPRY2 protein, human; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2; D049452:Green Fluorescent Proteins