The role of small G proteins of the ADP-ribosylation factor (ARF) and Rho families on the activation of phospholipase D (PLD) by platelet-derived growth factor (PDGF) and phorbol esters (PMA) has been investigated. The activation of PLD by PDGF and PMA was blocked by brefeldin A (BFA), an inhibitor of ARF activation, but not by Clostridium botulinum C3 exotoxin, an inhibitor of the activity of Rho. PDGF and PMA, in the presence of GTPγS, promoted the association of ARF and RhoA with cell membranes. Cells depleted of ARF and Rho by digitonin permeabilization showed a significant reduction of the activity of phospholipase D. Recombinant ARF was sufficient to restore agonist-induced PLD activity to digitonin-permeabilized, cytoplasm-depleted cells. In contrast, isoprenylated recombinant RhoA had no effects in this reconstitution assay. HIRcB cells were transiently transfected with wild-type and dominant-negative mutants of ARF1 and ARF6. Neither wt-ARF1 nor wt-ARF6 had any effects on agonist-dependent PLD activity. However, dominant-negative ARF1 and ARF6 mutants blocked the stimulation of PLD by PDGF but only partially inhibited the effects of PMA. These results demonstrate that ARF rather than Rho proteins mediate the activation of PLD by PDGF and phorbol esters in HIRcB fibroblasts.
ABSTRACT
PUBLICATION RECORD
- Publication year
1998
- Venue
Journal of Biological Chemistry
- Publication date
1998-11-13
- Fields of study
Biology, Medicine, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- adp-ribosylation factor proteins
A family of small GTP-binding proteins examined here for their role in agonist-induced phospholipase D activation.
Aliases: ARF proteins, ARF
- arf1
A specific ARF-family small GTPase tested as wild-type and dominant-negative constructs.
- arf6
A specific ARF-family small GTPase tested as wild-type and dominant-negative constructs.
- digitonin permeabilization
A membrane-permeabilization procedure used to deplete cells of cytoplasmic factors before reconstitution.
Aliases: digitonin-permeabilized cells
- hircb cells
The fibroblast cell line used for transfection and agonist-response experiments.
Aliases: HIRcB fibroblasts
- phorbol esters
Protein kinase C-activating agonists represented in the experiments by PMA.
Aliases: PMA
- phospholipase d
An enzyme whose activity was measured after agonist stimulation in the fibroblast assays.
Aliases: PLD
- platelet-derived growth factor
A growth factor agonist used to stimulate phospholipase D in HIRcB fibroblasts.
Aliases: PDGF
- rho proteins
A family of small GTP-binding proteins compared with ARF proteins in the phospholipase D assays.
Aliases: Rho family
REFERENCES
Showing 1-38 of 38 references · Page 1 of 1
CITED BY
Showing 1-69 of 69 citing papers · Page 1 of 1