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Proteomic analysis reveals the composition of glutamatergic organelles of auditory inner hair cells

ABSTRACT: In the ear, inner hair cells (IHCs) employ sophisticated glutamatergic ribbon synapses with afferent neurons to transmit auditory information to the brain. The presynaptic machinery responsible for neurotransmitter release in IHC synapses includes proteins such as the multi-C2-domain protein otoferlin and the vesicular glutamate transporter 3 (VGluT3). Yet, much of this likely unique molecular machinery remains to be deciphered. The scarcity of material has so far hampered biochemical studies which require large amounts of purified sample. We developed a subcellular fractionation workflow combined with immunoisolation of VGluT3-containing membrane vesicles, allowing for the enrichment of IHC trafficking glutamatergic organelles that are likely dominated by synaptic vesicles (SVs) of IHCs. We have characterized their protein composition in mice before and after hearing onset using mass spectrometry and confocal imaging and provide a fully annotated proteome with hitherto unidentified proteins. Despite the prevalence of IHC marker proteins across IHC maturation, the profiles of trafficking proteins differed markedly before and after hearing onset. Our study provides an inventory of the machinery associated with synaptic vesicle-mediated trafficking and presynaptic activity at IHC ribbon synapses and serves as a foundation for future functional studies.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Cochlear Inner Hair Cell, Inner Ear

SUBMITTER: Andreia P. Cepeda

LAB HEAD: Henning Urlaub

PROVIDER: PXD046664 | Pride | 2024-02-09

REPOSITORIES: pride

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			Action	DRS
	ACepeda_080621_140621_Expl1_L1_R1_1.raw	Raw
	ACepeda_080621_140621_Expl1_L1_R1_10.raw	Raw
	ACepeda_080621_140621_Expl1_L1_R1_2.raw	Raw
	ACepeda_080621_140621_Expl1_L1_R1_3.raw	Raw
	ACepeda_080621_140621_Expl1_L1_R1_4.raw	Raw

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Proteomic analysis reveals the composition of glutamatergic organelles of auditory inner hair cells

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