Arfaptin 1 forms a complex with ADP-ribosylation factor and inhibits phospholipase D.
ADP-ribosylation factors (ARFs) regulate coatomer assembly on the Golgi as well as recruitment of clathrin adapter proteins and are therefore involved in vesicle budding from the Golgi and vesicular transport. They are also regulators of phospholipase D (PLD) activity. Arfaptin 1 is an ARF binding protein that inhibits PLD activation, vesicular trafficking and secretion. In the present report, we show that arfaptin 1 interacts with 'high speed' membranes independently of ARF. However, addition of myristoylated ARF3 (myrARF3) increases the association of arfaptin 1 with the membranes, suggesting that arfaptin 1 and ARF form a complex on the Golgi. Utilizing several deletion mutants of arfaptin 1 it is shown that the association of arfaptin 1 with myrARF3 is mediated via two binding sites on arfaptin 1. These two domains are needed for arfaptin 1 inhibition of PLD activation by myrARF3 in vitro.
Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0295, USA.
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BT
Williger
J J
JJ
Provost
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WT
Ho
J
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Milstine
J H
JH
Exton
D020727:ADP-Ribosylation Factors; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects; D008099:Liver / Q000378:metabolism; D010739:Phospholipase D / Q000037:antagonists & inhibitors*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C105088:ARFIP1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D010739:Phospholipase D; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors