Major Vault Protein Is a Substrate of Endogenous Protein Kinases in CHO and PC12 Cells
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C. Ehrnsperger
Abstract
Major vault protein (MVP) is the predominant member of a large cytosolic ribonucleoprotein particle, termed vault. We have previously shown that MVP derived from electric ray electric organ becomes phosphorylated by protein kinase C in vitro and by tyrosine kinase in vivo. Here we show that MVP from two mammalian cell lines (CHO and PC12 cell) becomes highly phosphorylated by endogenous protein kinases in cellfree systems. The susceptibility to protein kinases differs substantially from those observed in MVP derived from electric organ. Phosphorylation of MVP depends on the presence of Mg2+ and can be inhibited by the chelating agent EDTA. Inhibitors of casein kinase II attenuate the phosphorylation of MVP. In contrast to CHO cells, addition of recombinant casein kinase II enhances the phosphorylation of MVP in PC12 cells. Endogenous kinase activity is of particulate nature and copurifies with vault particles. Immunoaffinity purified vaults containing recombinant tagged MVP expressed in CHO cells reveal no autophosphorylation, suggesting that protein kinase activity is not an intrinsic property of vaults. Our results suggest that cellspecific phosphorylation of MVP may play a critical role in vault function.
Copyright © 2001 by Walter de Gruyter GmbH & Co. KG
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- Protein-DNA Interaction and CpG Methylation at rep*/vIL-10p of Latent Epstein-Barr Virus Genomes in Lymphoid Cell Lines
- In Vitro and in Vivo Processing of Cyanelle tmRNA by RNase P
- A Eubacterial Origin for the Human tRNA Nucleotidyltransferase?
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- The MKK6/p38 Mitogen-Activated Protein Kinase Pathway Is Capable of Inducing SOCS3 Gene Expression and Inhibits IL-6-Induced Transcription
- Identification of a Gephyrin-Binding Motif in the GDP/GTP Exchange Factor Collybistin
- Major Vault Protein Is a Substrate of Endogenous Protein Kinases in CHO and PC12 Cells
- Identification of Receptors for Prothymosin α on Human Lymphocytes
- Tissue Kallikrein KLK1 Is Expressed de Novo in Endothelial Cells and Mediates Relaxation of Human Umbilical Veins
- Secretion of Gelatinases and Activation of Gelatinase A (MMP-2) by Human Rheumatoid Synovial Fibroblasts
- Ferredoxins from the Archaeon Acidianus ambivalens: Overexpression and Characterization of the Non-Zinc-Containing Ferredoxin FdB
- Isolation and Characterization of a Trypsin-Like Protease from Trichoderma viride
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