Identification of new substrates of the protein-tyrosine phosphatase PTP1B by Bayesian integration of proteome evidence.
There is growing evidence that tyrosine phosphatases display an intrinsic enzymatic preference for the sequence context flanking the target phosphotyrosines. On the other hand, substrate selection in vivo is decisively guided by the enzyme-substrate connectivity in the protein interaction network. We describe here a system wide strategy to infer physiological substrates of protein-tyrosine phosphatases. Here we integrate, by a Bayesian model, proteome wide evidence about in vitro substrate preference, as determined by a novel high-density peptide chip technology, and "closeness" in the protein interaction network. This allows to rank candidate substrates of the human PTP1B phosphatase. Ultimately a variety of in vitro and in vivo approaches were used to verify the prediction that the tyrosine phosphorylation levels of five high-ranking substrates, PLC-γ1, Gab1, SHP2, EGFR, and SHP1, are indeed specifically modulated by PTP1B. In addition, we demonstrate that the PTP1B-mediated dephosphorylation of Gab1 negatively affects its EGF-induced association with the phosphatase SHP2. The dissociation of this signaling complex is accompanied by a decrease of ERK MAP kinase phosphorylation and activation.
Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00144 Rome, Italy.
Emanuela
E
Ferrari
Michele
M
Tinti
Stefano
S
Costa
Salvatore
S
Corallino
Aurelio Pio
AP
Nardozza
Andrew
A
Chatraryamontri
Arnaud
A
Ceol
Gianni
G
Cesareni
Luisa
L
Castagnoli
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D002460:Cell Line; D066246:ErbB Receptors / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051966:Phospholipase C gamma / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D040081:Protein Array Analysis / Q000379:methods; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000378:metabolism*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D013379:Substrate Specificity / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; C098587:GAB1 protein, human; D020543:Proteome; C512478:EGFR protein, human; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C522157:PLCG1 protein, human; D051966:Phospholipase C gamma