PUBLICATION
Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein Pathway, Disrupts Photoreceptor Synapse Structure and Function
- Authors
- Daniele, L.L., Emran, F., Lobo, G.P., Gaivin, R.J., Perkins, B.D.
- ID
- ZDB-PUB-160610-10
- Date
- 2016
- Source
- Investigative ophthalmology & visual science 57: 2942-54 (Journal)
- Registered Authors
- Daniele, Lauren, Emran, Farida, Gaivin, Bob, Lobo, Glenn, Perkins, Brian
- Keywords
- none
- MeSH Terms
-
- Animals
- Electroretinography
- Endoplasmic Reticulum/metabolism
- Membrane Proteins/metabolism
- Mutation*
- Nuclear Proteins/genetics*
- Nuclear Proteins/metabolism
- Photoreceptor Cells/physiology*
- Protein Processing, Post-Translational/physiology
- Protein Transport/physiology*
- Qa-SNARE Proteins/genetics
- Qa-SNARE Proteins/metabolism
- Synapses/metabolism
- Synapses/pathology
- Synapses/physiology
- Synaptic Transmission/physiology*
- Zebrafish
- Zebrafish Proteins/genetics
- PubMed
- 27273592 Full text @ Invest. Ophthalmol. Vis. Sci.
Citation
Daniele, L.L., Emran, F., Lobo, G.P., Gaivin, R.J., Perkins, B.D. (2016) Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein Pathway, Disrupts Photoreceptor Synapse Structure and Function. Investigative ophthalmology & visual science. 57:2942-54.
Abstract
Purpose Tail-anchored (TA) proteins contain a single hydrophobic domain at the C-terminus and are posttranslationally inserted into the ER membrane via the GET (guided entry of tail-anchored proteins) pathway. The role of the GET pathway in photoreceptors is unexplored. The goal of this study was to characterize the zebrafish pinball wizard mutant, which disrupts Wrb, a core component of the GET pathway.
Methods Electroretinography, optokinetic response measurements (OKR), immunohistochemistry, and electron microscopy analyses were employed to assess ribbon synapse function, protein expression, and ultrastructure in 5-day-old zebrafish larvae. Expression of wrb was investigated with real-time qRT-PCR and in situ hybridization.
Results Mutation of wrb abolished the OKR and greatly diminished the ERG b-wave, but not the a-wave. Ribeye and SV2 were partially mislocalized in both photoreceptors and hair cells of wrb mutants. Fewer contacts were seen between photoreceptors and bipolar cells in wrb-/- mutants. Expression of wrb was observed throughout the nervous system and Wrb localized to the ER and synaptic region of photoreceptors. Morpholino knockdown of the cytosolic ATPase trc40, which targets TA proteins to the ER, also diminished the OKR. Overexpression of wrb fully restored contrast sensitivity in mutants, while overexpression of mutant wrbR73A, which cannot bind Trc40, did not.
Conclusions Proteins Wrb and Trc40 are required for synaptic transmission between photoreceptors and bipolar cells, indicating that TA protein insertion by the TRC pathway is a critical step in ribbon synapse assembly and function.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping