Title
Epileptic encephalopathy-causing mutations in DNM1 impair synaptic vesicle endocytosis.
Document Type
Article
Publication Date
4-17-2015
JAX Source
Neurol Genet 2015 Apr 17; 1(1) e4.
Volume
1
Issue
1
First Page
4
Last Page
4
ISSN
2376-7839
PMID
27066543
Abstract
OBJECTIVE: To elucidate the functional consequences of epileptic encephalopathy-causing de novo mutations in DNM1 (A177P, K206N, G359A), which encodes a large mechanochemical GTPase essential for neuronal synaptic vesicle endocytosis.
METHODS: HeLa and COS-7 cells transfected with wild-type and mutant DNM1 constructs were used for transferrin assays, high-content imaging, colocalization studies, Western blotting, and electron microscopy (EM). EM was also conducted on the brain sections of mice harboring a middle-domain Dnm1 mutation (Dnm1 (Ftfl)).
RESULTS: We demonstrate that the expression of each mutant protein decreased endocytosis activity in a dominant-negative manner. One of the G-domain mutations, K206N, decreased protein levels. The G359A mutation, which occurs in the middle domain, disrupted higher-order DNM1 oligomerization. EM of mutant DNM1-transfected HeLa cells and of the Dnm1 (Ftfl) mouse brain revealed vesicle defects, indicating that the mutations likely interfere with DNM1's vesicle scission activity.
CONCLUSION: Together, these data suggest that the dysfunction of vesicle scission during synaptic vesicle endocytosis can lead to serious early-onset epilepsies.
Neurol Genet 2015 Apr 17; 1(1) e4.
Recommended Citation
Dhindsa R,
Bradrick S,
Yao X,
Heinzen E,
Petrovski S,
Krueger B,
Johnson M,
Frankel W,
Petrou S,
Boumil RM,
Goldstein D.
Epileptic encephalopathy-causing mutations in DNM1 impair synaptic vesicle endocytosis. Neurol Genet 2015 Apr 17; 1(1) e4.