Hongying Ma1, Shenglei Feng1, Xuejun Deng2, Li Wang1, Sheng Zeng3, Cheng Wang1, Xixiang Ma1, Hao Sun1, Rui Chen1, Shiyue Du1, Jinglin Mao1, Xianwei Zhang4, Cong Ma1, Hong Jiang3, Luoying Zhang1, Beisha Tang3, Jing Yu Liu1. 1. Key Laboratory of Molecular Biophysics of the Ministry of Education, Center for Human Genome Research, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. 2. Department of Neurology, Union Hospital of Huazhong University of Science and Technology, Wuhan, China. 3. Department of Neurology, Xiangya Hospital, Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China. 4. Department of Anesthesiology, Tongji Hospital of Huazhong University of Science and Technology, Wuhan, China.
Abstract
OBJECTIVE: To identify the causative gene of autosomal dominant paroxysmal kinesigenic dyskinesia and benign familial infantile seizures (PKD/BFIS) in a large Chinese family and explore the potential pathogenic mechanism of a PRRT2 (proline-rich transmembrane protein 2) variant. METHODS: Genetic testing was performed via whole exome sequencing. Western blotting and immunofluorescence were used to analyze the protein expression level and subcellular localization of the PRRT2 mutant in HeLa cells and N2A cells. Coimmunoprecipitation was conducted to investigate the interaction of the PRRT2 mutant with syntaxin 1B (STX1B). RESULTS: In a large Chinese family with autosomal dominant PKD/BFIS showing wide phenotypic heterogeneity, including patients suffering from PKD, BFIS, or epilepsy and asymptomatic variant carriers, a c.621dupA variant in PRRT2 was identified in the proband and was shown to cosegregate with the phenotype in this family. This variant results in premature termination at codon 224, producing a truncated protein (p.Ser208Ilefs*17) in which the two conserved hydrophobic segments and the cytoplasmic loop are missing. Both the expression and subcellular localization of PRRT2 are strongly affected by the c.621dupA variant. In addition, we found that PRRT2 directly interacts with STX1B, a SNARE protein critical for neurotransmitter release, whereas the truncated variant p.Ser208Ilefs*17 lacking the helix-loop-helix domain fails to bind to STX1B. SIGNIFICANCE: Our findings identified a PRRT2 variant in a family with PKD/BFIS and confirmed STX1B as a new binding partner of PRRT2, which suggested that the loss of the interaction between PRRT2 and STX1B may contribute to the pathogenesis of PKD/BFIS. Wiley Periodicals, Inc.
OBJECTIVE: To identify the causative gene of autosomal dominant paroxysmal kinesigenic dyskinesia and benign familial infantile seizures (PKD/BFIS) in a large Chinese family and explore the potential pathogenic mechanism of a PRRT2 (proline-rich transmembrane protein 2) variant. METHODS: Genetic testing was performed via whole exome sequencing. Western blotting and immunofluorescence were used to analyze the protein expression level and subcellular localization of the PRRT2 mutant in HeLa cells and N2A cells. Coimmunoprecipitation was conducted to investigate the interaction of the PRRT2 mutant with syntaxin 1B (STX1B). RESULTS: In a large Chinese family with autosomal dominant PKD/BFIS showing wide phenotypic heterogeneity, including patients suffering from PKD, BFIS, or epilepsy and asymptomatic variant carriers, a c.621dupA variant in PRRT2 was identified in the proband and was shown to cosegregate with the phenotype in this family. This variant results in premature termination at codon 224, producing a truncated protein (p.Ser208Ilefs*17) in which the two conserved hydrophobic segments and the cytoplasmic loop are missing. Both the expression and subcellular localization of PRRT2 are strongly affected by the c.621dupA variant. In addition, we found that PRRT2 directly interacts with STX1B, a SNARE protein critical for neurotransmitter release, whereas the truncated variant p.Ser208Ilefs*17 lacking the helix-loop-helix domain fails to bind to STX1B. SIGNIFICANCE: Our findings identified a PRRT2 variant in a family with PKD/BFIS and confirmed STX1B as a new binding partner of PRRT2, which suggested that the loss of the interaction between PRRT2 and STX1B may contribute to the pathogenesis of PKD/BFIS. Wiley Periodicals, Inc.
Authors: Eliyahu Perl; Padmapriyadarshini Ravisankar; Manu E Beerens; Lejla Mulahasanovic; Kelly Smallwood; Marion Bermúdez Sasso; Carina Wenzel; Thomas D Ryan; Matej Komár; Kevin E Bove; Calum A MacRae; K Nicole Weaver; Carlos E Prada; Joshua S Waxman Journal: HGG Adv Date: 2022-04-27