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Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Evidence that dynamin-2 functions as a signal-transducing GTPase
K N Fish1, S L Schmid, H Damke
1Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
The Journal of Cell Biology
|July 13, 2000
Summary
Dynamin-2 (dyn2), a protein involved in cell uptake, can trigger cell death (apoptosis) by activating the p53 pathway. This occurs in dividing cells when dyn2 levels increase, suggesting a new role for dyn2 in signal transduction.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Dynamin GTPases are crucial for receptor-mediated endocytosis.
- The ubiquitously expressed dynamin-2 (dyn2) isoform's role beyond endocytosis is less understood.
Purpose of the Study:
- To investigate potential signal transduction roles of dynamin-2.
- To determine the molecular mechanisms by which dyn2 might influence cellular processes.
Main Methods:
- Overexpression of wild-type and mutant dynamin-2 in dividing cells.
- Assays for cell proliferation, DNA fragmentation, and caspase-3 activation.
- Analysis of p53-dependent apoptosis and specificity compared to dynamin-1.
Main Results:
- A moderate increase in dynamin-2 levels activates the transcription factor p53, inducing apoptosis.
- Dyn2-induced apoptosis is p53-dependent and occurs specifically in dividing cells.
- A dynamin-2 mutant defective in GTP binding does not induce apoptosis, indicating the active GTP-bound form is signaling-competent.
- A truncated dyn2 mutant lacking the proline/arginine-rich domain (PRD) is a more potent inducer of apoptosis.
Conclusions:
- Dynamin-2 functions as a signal transducing GTPase, capable of activating p53 and inducing apoptosis.
- The GTPase activity and NH(2)-terminal domain of dyn2 are critical for its pro-apoptotic signaling.
- Dynamin-2 plays a novel role in regulating cell fate decisions through transcriptional regulation.
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