KCNC3(R420H), a K(+) channel mutation causative in spinocerebellar ataxia 13 displays aberrant intracellular trafficking

Authors

Carolina Gallego-Iradi, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Justin S. Bickford, Department of Neuroscience College of Medicine, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Swati Khare, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Alexis Hall, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Jerelyn A. Nick, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Donya Salmasinia, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Kolja Wawrowsky, Department of Endocrinology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Serguei Bannykh, Department of Pathology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Duong P. Huynh, Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84123, USA.
Diego E. Rincon-Limas, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Stefan M. Pulst, Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84123, USA.
Harry S. Nick, Department of Neuroscience College of Medicine, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Pedro Fernandez-Funez, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience College of Medicine, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Michael F. Waters, Department of Neurology, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience College of Medicine, University of Florida, Gainesville, FL 32611, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32611, USA. Electronic address: mwaters@neurology.ufl.edu.

Document Type

Article

Abstract

Spinocerebellar ataxia 13 (SCA13) is an autosomal dominant disease resulting from mutations in KCNC3 (Kv3.3), a voltage-gated potassium channel. The KCNC3(R420H) mutation was first identified as causative for SCA13 in a four-generation Filipino kindred with over 20 affected individuals. Electrophysiological analyses in oocytes previously showed that this mutation did not lead to a functional channel and displayed a dominant negative phenotype. In an effort to identify the molecular basis of this allelic form of SCA13, we first determined that human KCNC3(WT) and KCNC3(R420H) display disparate post-translational modifications, and the mutant protein has reduced complex glycan adducts. Immunohistochemical analyses demonstrated that KCNC3(R420H) was not properly trafficking to the plasma membrane and surface biotinylation demonstrated that KCNC3(R420H) exhibited only 24% as much surface expression as KCNC3(WT). KCNC3(R420H) trafficked through the ER but was retained in the Golgi. KCNC3(R420H) expression results in altered Golgi and cellular morphology. Electron microscopy of KCNC3(R420H) localization further supports retention in the Golgi. These results are specific to the KCNC3(R420H) allele and provide new insight into the molecular basis of disease manifestation in SCA13.

Keywords

Dominant inheritance, Golgi, KCNC3, Protein trafficking, SCA13, Spinocerebellar ataxia, Voltage-gated potassium channel

Medical Subject Headings

Animals; Animals, Genetically Modified; Arginine (genetics); Biotinylation; COS Cells; Cadherins (metabolism); Chlorocebus aethiops; Cytoplasm (genetics, metabolism); Drosophila; Drosophila Proteins (genetics); Endoplasmic Reticulum (metabolism); Female; Histidine (genetics); Humans; Intracellular Fluid (metabolism); Male; Mutation (genetics); Oocytes; Protein Processing, Post-Translational; Protein Transport; Shaw Potassium Channels (genetics); Spinocerebellar Ataxias (congenital); Spinocerebellar Degenerations (genetics, metabolism); Transfection

Publication Date

11-1-2014

Publication Title

Neurobiology of disease

E-ISSN

1095-953X

Volume

71

First Page

270

Last Page

9

PubMed ID

25152487

Digital Object Identifier (DOI)

10.1016/j.nbd.2014.08.020

Recommended Citation

Gallego-Iradi, Carolina; Bickford, Justin S.; Khare, Swati; Hall, Alexis; Nick, Jerelyn A.; Salmasinia, Donya; Wawrowsky, Kolja; Bannykh, Serguei; Huynh, Duong P.; Rincon-Limas, Diego E.; Pulst, Stefan M.; Nick, Harry S.; Fernandez-Funez, Pedro; and Waters, Michael F., "KCNC3(R420H), a K(+) channel mutation causative in spinocerebellar ataxia 13 displays aberrant intracellular trafficking" (2014). Translational Neuroscience. 1326.
https://scholar.barrowneuro.org/neurobiology/1326