Epileptic encephalopathy-causing mutations in DNM1 impair synaptic vesicle endocytosis
Citation Manager Formats
Make Comment
See Comments

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 (Dnm1Ftfl).
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 Dnm1Ftfl 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.
GLOSSARY
- DAPI=
- 4',6-diamidino-2-phenylindole;
- EDC=
- 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide;
- EM=
- electron microscopy;
- GFP=
- green fluorescent protein;
- LGS=
- Lennox-Gastaut syndrome;
- RFP=
- red fluorescent protein;
- RIPA=
- radioimmunoprecipitation assay;
- TBS=
- Tris-buffered saline;
- WT=
- wild type
Footnotes
Funding information and disclosures are provided at the end of the article. Go to Neurology.org/ng for full disclosure forms. The Article Processing Charge was paid by the authors.
Supplemental data at Neurology.org/ng
- Received March 1, 2015.
- Accepted in final form March 20, 2015.
- © 2015 American Academy of Neurology
This is an open access article distributed under the terms of the Creative Commons Attribution-Noncommercial No Derivative 3.0 License, which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially.
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
You May Also be Interested in
Dr. Nicole Sur and Dr. Mausaminben Hathidara
► Watch
Alert Me
Recommended articles
-
Articles
CACNA1A mutations causing episodic and progressive ataxia alter channel trafficking and kineticsJ. Wan, R. Khanna, M. Sandusky et al.Neurology, June 27, 2005 -
Article
DPAGT1 myasthenia and myopathyGenetic, phenotypic, and expression studiesDuygu Selcen, Xin-Ming Shen, Joan Brengman et al.Neurology, April 23, 2014 -
Articles
Loss-of-function EA2 mutations are associated with impaired neuromuscular transmissionJ. Jen, J. Wan, M. Graves et al.Neurology, November 27, 2001 -
Articles
A novel de novo mutation in the desmin gene causes desmin myopathy with toxic aggregatesM. Sugawara, K. Kato, M. Komatsu et al.Neurology, October 10, 2000