The ion transport peptide is a new brain chemical that helps control the internal clock in fruit flies

The ion transport peptide (ITP) may play a significant role in regulating behavioral rhythms in Drosophila melanogaster.

• ITP is expressed in specific neurons associated with the circadian clock and in a few nonclock cells in the brain.
• Immunocytochemical analyses suggest that ITP is released rhythmically in the dorsal protocerebrum, controlled by the biological clock.
• A reduction in ITP expression was observed in the Clk(AR) mutant, indicating regulation by the CLOCK protein.
• Knockdown of ITP in clock cells resulted in reduced evening activity and increased nocturnal activity in flies.
• Overexpression of ITP disrupted behavioral rhythms while only slightly affecting the cycling of a key clock protein.
• Simultaneous knockdown of ITP and PDF led to hyperactivity and near-complete arrhythmia in constant conditions.

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