Sprouty proteins inhibit receptor-mediated activation of phosphatidylinositol-specific phospholipase C.
Sprouty (Spry) proteins are negative regulators of receptor tyrosine kinase signaling; however, their exact mechanism of action remains incompletely understood. We identified phosphatidylinositol-specific phospholipase C (PLC)-γ as a partner of the Spry1 and Spry2 proteins. Spry-PLCγ interaction was dependent on the Src homology 2 domain of PLCγ and a conserved N-terminal tyrosine residue in Spry1 and Spry2. Overexpression of Spry1 and Spry2 was associated with decreased PLCγ phosphorylation and decreased PLCγ activity as measured by production of inositol (1,4,5)-triphosphate (IP(3)) and diacylglycerol, whereas cells deficient for Spry1 or Spry1, -2, and -4 showed increased production of IP(3) at baseline and further increased in response to growth factor signals. Overexpression of Spry 1 or Spry2 or small-interfering RNA-mediated knockdown of PLCγ1 or PLCγ2 abrogated the activity of a calcium-dependent reporter gene, suggesting that Spry inhibited calcium-mediated signaling downstream of PLCγ. Furthermore, Spry overexpression in T-cells, which are highly dependent on PLCγ activity and calcium signaling, blocked T-cell receptor-mediated calcium release. Accordingly, cultured T-cells from Spry1 gene knockout mice showed increased proliferation in response to T-cell receptor stimulation. These data highlight an important action of Spry, which may allow these proteins to influence signaling through multiple receptors.
Akbulut
Simge
S
Division of Hematology and Oncology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Reddi
Alagarsamy L
AL
Aggarwal
Priya
P
Ambardekar
Charuta
C
Canciani
Barbara
B
Kim
Marianne K H
MK
Hix
Laura
L
Vilimas
Tomas
T
Mason
Jacqueline
J
Basson
M Albert
MA
Lovatt
Matthew
M
Powell
Jonathan
J
Collins
Samuel
S
Quatela
Steven
S
Phillips
Mark
M
Licht
Jonathan D
JD
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation; D047468:Immunoprecipitation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D042541:Intracellular Space / Q000378:metabolism; D037181:Lectins, C-Type / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D041681:NIH 3T3 Cells; D051966:Phospholipase C gamma / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism; D014158:Transcription, Genetic; D018631:ras Proteins / Q000378:metabolism; D000099192:CD69 Antigens
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D015415:Biomarkers; D002118:Calcium; D004075:Diglycerides; D015544:Inositol 1,4,5-Trisphosphate; D047908:Intracellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases; D051966:Phospholipase C gamma; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011948:Receptors, Antigen, T-Cell; D018631:ras Proteins; D000099192:CD69 Antigens; C011439:1,2-diacylglycerol; C425468:Spry1 protein, mouse; C118389:Spry2 protein, mouse