Phosphorylation of the mRNA cap binding protein and eIF-4A by different protein kinases

Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6074763

Hagedorn, C H

These studies were done to determine the identity of a protein kinase that phosphorylates the mRNA cap binding protein (CBP). Two chromatographic steps (dye and ligand and ion exchange HPLC) produced a 500x purification of an enzyme activity in rabbit reticulocytes that phosphorylated CBP at serine residues. Isoelectric focusing analysis of kinase treated CBP demonstrated 5 isoelectric species of which the 2 most anodic species were phosphorylated (contained /sup 32/P). This kinase activity phosphorylated CBP when it was isolated or in the eIF-4F complex. Purified protein kinase C, cAMP or cGMP dependent protein kinase, casein kinase I or II, myosin light chain kinase or insulin receptor kinase did not significantly phosphorylate isolated CBP or CBP in the eIF-4F complex. However, cAMP and cGMP dependent protein kinases and casein kinase II phosphorylated eIF-4A but did not phosphorylate the 46 kDa component of eIF-4F. cAMP dependent protein kinase phosphorylated a approx. 220 kDa protein doublet in eIF-4F preparations. These studies indicate that CBP kinase activity probably represents a previously unidentified protein kinase. In addition, eIF-4A appears to be phosphorylated by several protein kinases whereas the 46 kDa component of the eIF-4F complex was not.

• Research Organization: Washington Univ. School of Medicine, St. Louis, MO
• OSTI ID: 6074763
• Report Number(s): CONF-870644-; TRN: 87-037129
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
PROTEINS
PHOSPHORYLATION
ION EXCHANGE CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
MESSENGER-RNA
PHOSPHORUS 32
RABBITS
RETICULOCYTES
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ENZYMES
ERYTHROCYTES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MATERIALS
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
RADIOISOTOPES
RNA
SEPARATION PROCESSES
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques