Document Detail


Cell signaling through the protein kinases cAMP-dependent protein kinase, protein kinase Cepsilon, and RAF-1 regulates amphotropic murine leukemia virus envelope protein-induced syncytium formation.
MedLine Citation:
PMID:  15741175     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Amphotropic murine leukemia virus (A-MuLV) utilizes the PiT2 sodium-dependent phosphate transporter as its cell surface receptor to infect mammalian cells. The process of A-MuLV infection requires cleavage of the R peptide from the envelope protein. This occurs within virions thereby rendering them competent to fuse with target cells. Envelope proteins lacking the inhibitory R peptide (e.g. envelope (R-) proteins) induce viral envelope-mediated cell-cell fusion (syncytium). Here we have performed studies to determine if cell signaling through protein kinases is involved in the regulation of PiT2-mediated A-MuLV envelope (R-)-induced syncytium formation. Truncated A-MuLV retroviral envelope protein lacking the inhibitory R peptide (R-) was used to induce viral envelope-mediated cell-cell fusion. Signaling through cyclic AMP to activate PKA was found to inhibit envelope-induced cell-cell fusion, whereas treatment of cells with PKA inhibitors H89, KT5720, and PKA Catalpha siRNA all enhanced this cell fusion process. It was noted that activation of PKC, as well as overexpression of PKCepsilon, up-regulated A-MuLV envelope protein-induced cell-cell fusion, whereas exposure to PKC inhibitors and expression of a kinase-inactive dominant-negative mutant of PKCepsilon (K437R) inhibited syncytium formation. v-ras transformed NIH3T3 cells were highly susceptible to A-MuLV envelope-induced cell-cell fusion, whereas expression of a dominant-negative mutant of Ras (N17Ras) inhibited this cell fusion process. Importantly, activation of Raf-1 protein kinase also is required for A-MuLV envelope-induced syncytium formation. Expression of constitutively active BXB Raf supported, whereas expression of a dominant-negative mutant of Raf-1 (Raf301) blocked, A-MuLV-induced cell-cell fusion. These results indicate that specific cell signaling components are involved in regulating PiT2-mediated A-MuLV-induced cell-cell fusion. Selective pharmacological modulation of these signaling components may be an effective means of altering cell susceptibility to viral-mediated cytopathic effects.
Authors:
Wei Wang; Zsolt Jobbagy; Terry H Bird; Maribeth V Eiden; Wayne B Anderson
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Publication Detail:
Type:  Journal Article     Date:  2005-03-01
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  280     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-04-25     Completed Date:  2005-06-21     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  16772-83     Citation Subset:  IM    
Affiliation:
Laboratory of Cellular Oncology, NCI, National Institutes of Health, Bethesda, MD 20892, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blotting, Western
Cell Fusion
Cell Line
Cricetinae
Cyclic AMP / chemistry
Cyclic AMP-Dependent Protein Kinases / chemistry,  physiology*
DNA / metabolism
Enzyme Activation
Enzyme Inhibitors / pharmacology
Epitopes / chemistry
Gene Products, env / genetics
Genes, Dominant
Giant Cells / metabolism
Leukemia Virus, Murine / metabolism
Membrane Fusion
Mice
NIH 3T3 Cells
Peptides / chemistry
Protein Kinase C / physiology*
Protein Kinase C-epsilon
Proto-Oncogene Proteins c-raf / metabolism,  physiology*
RNA, Small Interfering / metabolism
Retroviridae / genetics
Signal Transduction*
Sodium-Phosphate Cotransporter Proteins
Sodium-Phosphate Cotransporter Proteins, Type III
Symporters / physiology*
Time Factors
Transfection
Up-Regulation
Viral Envelope Proteins / chemistry
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 0/Epitopes; 0/Gene Products, env; 0/Peptides; 0/RNA, Small Interfering; 0/Sodium-Phosphate Cotransporter Proteins; 0/Sodium-Phosphate Cotransporter Proteins, Type III; 0/Symporters; 0/Viral Envelope Proteins; 60-92-4/Cyclic AMP; 9007-49-2/DNA; EC 2.7.1.-/Prkce protein, mouse; EC 2.7.11.1/Proto-Oncogene Proteins c-raf; EC 2.7.11.11/Cyclic AMP-Dependent Protein Kinases; EC 2.7.11.13/Protein Kinase C; EC 2.7.11.13/Protein Kinase C-epsilon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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