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Heterogeneous N-acylation is a tissue- and species-specific posttranslational modification
R S Johnson1, H Ohguro, K Palczewski
1Department of Biochemistry, University of Washington, Seattle 98195.
The Journal of Biological Chemistry
|August 19, 1994
Summary
N-terminal glycine acylation in proteins is tissue-specific, not protein-specific. Retina proteins show varied fatty acid modifications, while heart and brain proteins are modified only with myristate.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Heterogeneous N-terminal glycine acylation, often involving myristate, has been observed in visual signal transduction proteins.
- Previous studies primarily examined proteins not isolated from retinal tissues.
Purpose of the Study:
- To investigate if heterogeneous N-acylation is specific to tissue type or protein sequence.
- To characterize the N-terminal modifications of the catalytic subunit of cAMP-dependent protein kinase from different bovine tissues.
Main Methods:
- Partial purification of the catalytic subunit of cAMP-dependent protein kinase from bovine retina, heart, and brain.
- Analysis using tandem mass spectrometry and liquid chromatography-electrospray mass spectrometry.
Main Results:
- Bovine brain and heart catalytic subunits showed N-terminal myristoylation exclusively.
- Bovine retina catalytic subunits exhibited heterogeneous N-acylation, similar to recoverin and transducin.
- Human recoverin displayed similar heterogeneous fatty acid modifications as bovine retinal proteins.
- Frog transducin showed homogeneous modification with a C14:2 unsaturated fatty acyl group, not myristate.
Conclusions:
- N-terminal glycine acylation is determined by the cell or tissue type, not the protein sequence.
- Heterogeneous N-acylation of retinal proteins is not exclusive to bovine species.
- Diverse fatty acyl modifications occur in retinal proteins across different species.