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Calcium-triggered (de)ubiquitination events in depolarized synaptosomes

ABSTRACT: Neurons communicate at synapses through the release of neurotransmitters (NT). These NTs are stored in synaptic vesicles (SVs) at the presynaptic nerve terminal, where they undergo a trafficking cycle consisting of Ca2+-triggered SV exocytosis, SV endocytosis and regeneration. While protein phosphorylation is known to fine-tune the SV trafficking cycle, another post-translational modification, protein ubiquitination, has been recently linked to NT release. However, the proteins and sites that undergo (de)ubiquitination at the synapse in response to Ca2+ influx remain unknown. Using a mass-spectrometry-based, quantification analysis of ubiquitinated proteins in isolated rat synaptosomes, we identified more than 5,000 ubiquitination sites on approximately 2,000 proteins. Among these, 41 proteins showed significant ubiquitination changes in response to Ca2+ influx, with Ca2+/calmodulin-dependent kinase II α (CaMKIIα) and the clathrin adaptor protein, AP180, showing the most pronounced changes. By expressing a fluorescence resonance energy transfer (FRET) probe, Camui, along with a mutant form lacking the ubiquitination target lysine site (K291), in non-neuronal and neuronal cells, we showed that K291 ubiquitination partially attenuates CaMKIIα activity and synaptic function.

INSTRUMENT(S): Q Exactive HF-X, Orbitrap Exploris 480

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Brain

SUBMITTER: Sofia Ainatzi

LAB HEAD: Henning Urlaub

PROVIDER: PXD052826 | Pride | 2025-04-18

REPOSITORIES: Pride

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			Action	DRS
	040321_uniprot_rat_UP000002494_BGD.fasta	Fasta
	MaxQuant_2.0.3.0.zip	Other
	MaxQuant_combined.zip	Other
	SAinatzi_040822_100822_Expl3_synapt54_SpikeTides_45fmol_KGG_PRM_R1_Ca01.raw	Raw
	SAinatzi_040822_100822_Expl3_synapt54_SpikeTides_45fmol_KGG_PRM_R1_Ca03.raw	Raw

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