Abstract
Endocytosis is inhibited by overexpression of either dynamin-1 or dynamin-2 mutants because both isoforms form heterotetramers with endogenous dynamin-2 and interfere with its function. By contrast, other phenotypes, which are specifically triggered by overexpression of dynamin-2, but not dynamin-1 are likely to reflect endocytosis-independent, dynamin-2-specific functions and/or interactions. Using Dyn2/Dyn1 chimeras, we explored the structural requirements for a readily quantifiable, isoform-specific function of dynamin-2, the activation of caspase-3 to trigger apoptosis. Strikingly, swapping the highly homologous GTPase domain of dynamin-2 into dynamin-1 was sufficient to confer caspase-3 activation. Moreover, assembly-defective mutations in GED, dynamin's GAP/assembly domain, that inhibit endocytosis enhance caspase-3 activation. Thus, this dynamin-2-specific function is mechanistically distinct from and independent of its role in endocytosis. These findings have important implications for interpreting dynamin-2 dependent phenotypes in overexpression studies.
Original language | English (US) |
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Pages (from-to) | 3539-3545 |
Number of pages | 7 |
Journal | Experimental Cell Research |
Volume | 312 |
Issue number | 18 |
DOIs | |
State | Published - Nov 1 2006 |
Keywords
- Apoptosis
- Caspase 3
- Dynamin
- Endocytosis
- GTPase
- p53
ASJC Scopus subject areas
- Cell Biology