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A cAMP-triggered release of a hormone-like peptide
R Riven-Kreitman1, V Ribon, M Tauber-Finkelstein
1Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
FEBS Letters
|November 7, 1988
Summary
Researchers discovered a peptide hormone-like factor (HLF) in protein kinase preparations. This factor, HLF, influences intracellular cyclic adenosine monophosphate (cAMP) levels in B-lymphoma cells.
Area of Science:
- Biochemistry
- Cellular Biology
- Molecular Endocrinology
Background:
- Preparations of the catalytic subunit of cAMP-dependent protein kinase (PKA) from rabbit skeletal muscle were analyzed.
- Homogeneous preparations, by SDS-PAGE, unexpectedly contained a hormone-like factor (HLF).
Purpose of the Study:
- To characterize the nature and activity of the identified hormone-like factor (HLF).
- To investigate the effect of HLF on intracellular cyclic adenosine monophosphate (cAMP) levels in a B-lymphoma cell line.
Main Methods:
- SDS-polyacrylamide gel electrophoresis (SDS-PAGE) for purity assessment.
- Incubation with cAMP and chromatography (including immobilized cAMP columns) for HLF activation and isolation.
- Proteolysis assays to determine peptide nature.
- Molecular mass estimation.
Main Results:
- HLF induces a transient increase and subsequent decrease in intracellular cAMP levels in B-lymphoma cells.
- HLF requires activation by cAMP prior to chromatographic separation.
- HLF is a peptide with a molecular mass of 2.2-2.5 kDa, as evidenced by loss of activity after proteolysis.
Conclusions:
- A novel peptide HLF associated with PKA preparations affects cellular cAMP signaling.
- HLF's activity is dependent on cAMP and its peptide nature suggests a role in intercellular communication or cellular regulation.