An unusual protein kinase phosphorylates the chemotactic receptor of Dictystelium discoideum

Journal Article · Fri Apr 01 00:00:00 EST 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.7.2181· OSTI ID:6828963

Meier, K; Klein, C ^[1]

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1. St. Louis Univ. School of Medicine, MO (USA)

The authors report the cAMP-dependent phosphorylation of the chemotactic receptor of Dictyostelium discoideum in partially purified plasma membranes. The protein kinase responsible for receptor phosphorylation is associated with this fraction and preferentially phosphorylates the ligand-occupied form of the receptor. 8-Azido({sup 32}P)cAMP labeling of the cell surface has shown that the cAMP receptor exists in two forms. A 45-kDa protein is predominant on unstimulated cells. cAMP stimulation results in an increased receptor phosphorylation such that the receptor migrates on NaDodSO{sub 4}/PAGE as a 47-kDa protein. Phosphorylation of the chemotactic receptor is not detected in membrane preparations unless cAMP is added to the incubation mixture. Only under those conditions is the phosphorylated 47-kDa form observed. The requirement for cAMP reflects the fact that the kinase involved preferentially uses the ligand-occupied receptor as a substrate. In vitro phosphorylation of the receptor does not involve tyrosine residues. The enzyme does not appear to be a cAMP- or cGMP-dependent protein kinase nor is it sensitive to guanine nucleotides, Ca{sup 2+}/calmodulin, Ca{sup 2+}/phospholipid, or EGTA. Similarities with the {beta}-adrenergic receptor protein kinase are discussed.

• OSTI ID: 6828963
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 85:7; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHOTRANSFERASES
BIOCHEMISTRY
RECEPTORS
CHEMICAL ACTIVATION
AMP
ATP
CELL MEMBRANES
ELECTROPHORESIS
LIGANDS
MYXOMYCETES
PHOSPHORUS 32
PHOSPHORYLATION
TRITIUM COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ENZYMES
FUNGI
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PLANTS
PROTEINS
RADIOISOTOPES
TRANSFERASES
550201* - Biochemistry- Tracer Techniques