The major vault protein is a novel substrate for the tyrosine phosphatase SHP-2 and scaffold protein in epidermal growth factor signaling.
The catalytic activity of the Src homology 2 (SH2) domain-containing tyrosine phosphatase, SHP-2, is required for virtually all of its signaling effects. Elucidating the molecular mechanisms of SHP-2 signaling, therefore, rests upon the identification of its target substrates. In this report, we have used SHP-2 substrate-trapping mutants to identify the major vault protein (MVP) as a putative SHP-2 substrate. MVP is the predominant component of vaults that are cytoplasmic ribonucleoprotein complexes of unknown function. We show that MVP is dephosphorylated by SHP-2 in vitro and it forms an enzyme-substrate complex with SHP-2 in vivo. In response to epidermal growth factor (EGF), SHP-2 associates via its SH2 domains with tyrosyl-phosphorylated MVP. MVP also interacts with the activated form of the extracellular-regulated kinases (Erks) in response to EGF and a constitutive complex between tyrosyl-phosphorylated MVP, SHP-2, and the Erks was detected in MCF-7 breast cancer cells. Using MVP-deficient fibroblasts, we demonstrate that MVP cooperates with Ras for optimal EGF-induced Elk-1 activation and is required for cell survival. We propose that MVP functions as a novel scaffold protein for both SHP-2 and Erk. The regulation of MVP tyrosyl phosphorylation by SHP-2 may play an important role in cell survival signaling.
Kolli
Sivanagarani
S
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066, USA.
Zito
Christina I
CI
Mossink
Marieke H
MH
Wiemer
Erik A C
EA
Bennett
Anton M
AM
D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors; D020394:Vault Ribonucleoprotein Particles / Q000235:genetics / Q000378:metabolism*; D050807:ets-Domain Protein Elk-1; D000099187:Major Vault Protein
D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D004815:Epidermal Growth Factor; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D014157:Transcription Factors; D020394:Vault Ribonucleoprotein Particles; D050807:ets-Domain Protein Elk-1; D000099187:Major Vault Protein; C494112:ELK1 protein, human; C494113:Elk1 protein, mouse; C516724:PTPN11 protein, human; C516725:Ptpn11 protein, mouse