Antagonism or synergism. Role of tyrosine phosphatases SHP-1 and SHP-2 in growth factor signaling.
SHP-1 and SHP-2 are two Src homology 2 domain-containing tyrosine phosphatases with major pathological implications in cell growth regulating signaling. They share significant overall sequence identity, but their biological functions are often opposite. SHP-1 is generally considered as a negative signal transducer and SHP-2 as a positive one. However, the precise role of each enzyme in shared signaling pathways is not well defined. In this study, we investigated the interaction of these two enzymes in a single cell system by knocking down their expressions with small interfering RNAs and analyzing the effects on epidermal growth factor signaling. Interestingly, knockdown of either SHP-1 or SHP-2 caused significant reduction in the activation of ERK1/2 but not Akt. Furthermore, SHP-1, SHP-2, and Gab1 formed a signaling complex, and SHP-1 and SHP-2 interact with each other. The interaction of SHP-1 with Gab1 is mediated by SHP-2 because it was abrogated by knockdown of SHP-2, and SHP-2, but not SHP-1, binds directly to tyrosine-phosphorylated Gab1. Together, the data revealed that both SHP-1 and SHP-2 have a positive role in epidermal growth factor-induced ERK1/2 activation and that they act cooperatively rather than antagonistically. The interaction of SHP-1 and SHP-2 may be responsible for previously unexpected novel regulatory mechanism of cell signaling by tyrosine phosphatases.
Wang
Ning
N
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Li
Zhe
Z
Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun 130023, China.
Ding
Ronghua
R
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Frank
Gerald D
GD
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Senbonmatsu
Takaaki
T
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Landon
Erwin J
EJ
Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Inagami
Tadashi
T
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232. Electronic address: tadashi.inagami@vanderbilt.edu.
Zhao
Zhizhuang Joe
ZJ
Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun 130023, China. Electronic address: joe-zhao@ouhsc.edu.
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D018938:Caco-2 Cells; D004815:Epidermal Growth Factor / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction
D048868:Adaptor Proteins, Signal Transducing; C098587:GAB1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D004815:Epidermal Growth Factor; D048052:Mitogen-Activated Protein Kinase 3; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases