TitleTruncation of the otoferlin transmembrane domain alters the development of hair cells and reduces membrane docking.
Publication TypeJournal Article
Year of Publication2021
AuthorsManchanda, A, Bonventre, JA, Bugel, SM, Chatterjee, P, Tanguay, R, Johnson, CP
JournalMol Biol Cell
Volume32
Issue14
Pagination1293-1305
Date Published2021 Jul 01
ISSN1939-4586
KeywordsAge Factors, Animals, Endocytosis, Exocytosis, Gene Expression, Hair Cells, Auditory, Humans, Membrane Proteins, Protein Domains, Synapses, Zebrafish
Abstract

Release of neurotransmitter from sensory hair cells is regulated by otoferlin. Despite the importance of otoferlin in the auditory and vestibular pathways, the functional contributions of the domains of the protein have not been fully characterized. Using a zebrafish model, we investigated a mutant otoferlin with a stop codon at the start of the transmembrane domain. We found that both the phenotype severity and the expression level of mutant otoferlin changed with the age of the zebrafish. At the early developmental time point of 72 h post fertilization, low expression of the otoferlin mutant coincided with synaptic ribbon deficiencies, reduced endocytosis, and abnormal transcription of several hair cell genes. As development proceeded, expression of the mutant otoferlin increased, and both synaptic ribbons and hair cell transcript levels resembled wild type. However, hair cell endocytosis deficits and abnormalities in the expression of GABA receptors persisted even after up-regulation of mutant otoferlin. Analysis of membrane-reconstituted otoferlin measurements suggests a function for the transmembrane domain in liposome docking. We conclude that deletion of the transmembrane domain reduces membrane docking, attenuates endocytosis, and results in developmental delay of the hair cell.

DOI10.1091/mbc.E20-10-0657
Alternate JournalMol Biol Cell
PubMed ID33979209
PubMed Central IDPMC8351550
Grant ListR01 DC014588 / DC / NIDCD NIH HHS / United States