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Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 10, 2010
Beta3A-adaptin, a subunit of the adaptor-like complex AP-3
E C Dell'Angelica1, C E Ooi, J S Bonifacino
1Cell Biology and Metabolism Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
The Journal of Biological Chemistry
|June 13, 1997
Summary
Researchers identified beta3A-adaptin, a subunit of the AP-3 complex involved in protein sorting. This ubiquitous protein is structurally similar to other adaptins, supporting AP-3
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Trafficking
Background:
- Adaptor protein complexes (AP) mediate protein sorting in exocytic/endocytic pathways.
- The AP-3 complex, involved in protein sorting, is widely expressed.
- AP-3 is composed of four distinct subunits.
Purpose of the Study:
- To identify and characterize a subunit of the AP-3 complex.
- To investigate the relationship between the identified subunit and other known adaptins.
- To determine the expression pattern and post-translational modifications of the identified subunit.
Main Methods:
- Protein identification and sequencing.
- Sequence comparison with known proteins.
- Co-purification and co-precipitation assays.
- In vivo phosphorylation analysis.
Main Results:
- Identification of beta3A-adaptin, a subunit of the AP-3 complex.
- Beta3A-adaptin shows sequence homology to beta-NAP, beta1-adaptin, and beta2-adaptin.
- Beta3A-adaptin is expressed ubiquitously and is phosphorylated in vivo.
- Beta3A-adaptin is not significantly found in clathrin-coated vesicles.
Conclusions:
- AP-3 complex, with beta3A-adaptin as a subunit, is a homolog of clathrin-associated adaptor complexes AP-1 and AP-2.
- Beta3A-adaptin's characteristics support its role in the AP-3 complex's function in protein sorting.
- The phosphorylation status of beta3A-adaptin may play a role in AP-3 complex regulation.
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