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© The Rockefeller University Press,
0021-9525/2000//145 $5.00
The Journal of Cell Biology, Volume 150, Number 1,
, 2000 145-154
Original Article |
Evidence That Dynamin-2 Functions as a Signal-Transducing Gtpase
damke{at}scripps.edu
The role of dynamin GTPases in the regulation of receptor-mediated endocytosis is well established. Here, we present new evidence that the ubiquitously expressed isoform dynamin-2 (dyn2) can also function in a signal transduction pathway(s). A
5-fold increase of dyn2 relative to endogenous levels activates the transcription factor p53 and induces apoptosis, as demonstrated by reduced cell proliferation, DNA fragmentation, and caspase-3 activation. Dyn2-triggered apoptosis occurs only in dividing cells and is p53 dependent. A mutant defective in GTP binding does not trigger apoptosis, indicating that increased levels of dyn2·GTP, rather than protein levels per se, are required to transduce signals that activate p53. A truncated dyn2 lacking the COOH-terminal proline/arginine-rich domain (PRD), which interacts with many SH3 domain-containing partners implicated in both endocytosis and signal transduction, triggers apoptosis even more potently than the wild-type. This observation provides additional support for the importance of the NH2-terminal GTPase domain for the apoptotic phenotype. All described effects are dyn2-specific because >200-fold overexpression of dyn1, the 70% identical neuronal isoform, has no effect. Our data suggest that dyn2 can act as a signal transducing GTPase affecting transcriptional regulation.
Key Words: dynamin apoptosis p53 GTPase endocytosis
© 2000 The Rockefeller University Press
The online version of this article contains supplemental material.Abbreviations used in this paper: Ad, adenovirus; dyn, dynamin; moi, multiplicity of infection; pfu, plaque forming unit; PRD, proline/arginine-rich domain; tTA, tetracycline-responsive transcription activator.
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