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Functional characterization of novel human ARFGAP3.
1Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Chinese National Human Genome Center at Beijing, 27 Taiping Road, Beijing 100850, P.R. China.
FEBS Letters
|February 15, 2001
Summary
We identified ARFGAP3, a novel GTPase-activating protein (GAP) that regulates ADP ribosylation factors (ARFs). ARFGAP3 controls vesicular transport and protein secretion by modulating ARF activity.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- ADP ribosylation factors (ARFs) are essential regulators of vesicular trafficking.
- GTPase-activating proteins (GAPs) control ARF activity.
- A novel ARF GAP, ARFGAP3, was identified from human fetal liver.
Purpose of the Study:
- To characterize the biochemical and functional properties of ARFGAP3.
- To investigate the role of ARFGAP3 in intracellular protein transport and vesicular trafficking.
Main Methods:
- In vitro assays to determine GAP activity.
- Phospholipid interaction studies.
- Cellular localization studies using overexpression in mammalian cells.
- Assay of secreted alkaline phosphatase secretion.
Main Results:
- ARFGAP3 exhibits GTPase-activating protein (GAP) activity towards ARF1 in vitro.
- ARFGAP3's GAP activity is modulated by phospholipids, with phosphatidylinositol 4,5-diphosphate as an agonist and phosphatidylcholine as an antagonist.
- ARFGAP3 is a cytosolic protein localized to the perinuclear region.
- Overexpression of ARFGAP3 inhibits the early secretory pathway, reducing protein secretion in vivo.
Conclusions:
- ARFGAP3 is a novel, phospholipid-regulated GAP for ARF1.
- ARFGAP3 plays a significant role in intracellular protein traffic and vesicular transport.
- ARFGAP3 is a potential regulator of the early secretory pathway.