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A Role for the Proteasome in the Light Response of the Timeless Clock Protein

Authors: N, Naidoo; W, Song; M, Hunter-Ensor; A, Sehgal;

A Role for the Proteasome in the Light Response of the Timeless Clock Protein

Abstract

The cyclic expression of the period (PER) and timeless (TIM) proteins is critical for the molecular circadian feedback loop in Drosophila. The entrainment by light of the circadian clock is mediated by a reduction in TIM levels. To elucidate the mechanism of this process, the sensitivity of TIM regulation by light was tested in an in vitro assay with inhibitors of candidate proteolytic pathways. The data suggested that TIM is degraded through a ubiquitin-proteasome mechanism. In addition, in cultures from third-instar larvae, TIM degradation was blocked specifically by inhibitors of proteasome activity. Degradation appeared to be preceded by tyrosine phosphorylation. Finally, TIM was ubiquitinated in response to light in cultured cells.

Related Organizations
Keywords

Neurons, Light, Leupeptins, Cysteine Proteinase Inhibitors, Darkness, Acetylcysteine, Circadian Rhythm, Feedback, Cysteine Endopeptidases, Biological Clocks, Leucine, Multienzyme Complexes, Animals, Drosophila Proteins, Insect Proteins, Drosophila, Protease Inhibitors, Phosphorylation, Phosphotyrosine, Cells, Cultured

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Powered by OpenAIRE graph
citations
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
238
Top 10%
Top 1%
Top 1%