circadian rhythm tagged posts

Highlights •Timeless interacts with PARP-1 independent of poly(ADP-ribosyl)ation •Crystal structures of Timeless PAB in free form and in complex with PARP-1 •Specific recognition of PARP-1 by Timeless does not affect its enzymatic activity •PARP-1 is required for Timeless recruitment to DSB sites to promote HR repair

A new molecular mechanism for DNA repair involving an unexpected interaction between PARP-1 protein and sleep proteins in humans has been found. While it is a well-known fact that sleep is important to the body’s recovery and healing, knowledge of the molecular mechanisms that make this possible is incomplete...

Credit: Vera Kratochvil/public domain

Shifting Sleep Cycle affects Immune response, sleep quality. Ilia Karatsoreos, an assistant professor in WSU’s Department of Integrative Physiology and Neuroscience, shifted mice from their usual cycle of sleeping and waking and saw that, while they got enough sleep, it was of poorer quality. The animals also had a disrupted immune response, leaving them more open to illness.

Most sleep research focuses on the effects of sleep deprivation or the overall amount of sleep an animal needs. This is generally referred to as sleep’s homeostatic process, which is driven by sleepiness or “sleep pressure.”
“…disruption of the circadian clock is nearly ubiquitous in our modern society” due to nighttime lighting, shift work, jet lag and even the blue-tinged light ...

Sleeping mouse (stock image). “What is amazing is finding the same mechanism for sleep-wake cycle control in an insect and a mammal,” said Matthieu Flourakis, the lead author of the study. “Mice are nocturnal, and flies are diurnal, or active during the day, but their sleep-wake cycles are controlled in the same way.” Credit: © Iosif Szasz-Fabian / Fotolia

In studies of fruit flies and mice and the brain circadian neurons governing the daily sleep-wake cycle’s timing, the researchers found that high sodium channel activity in these neurons during the day turn the cells on and ultimately awaken an animal, and high potassium channel activity at night turn them off, allowing the animal to sleep.

“This suggests the underlying mechanism controlling our sleep-wake cycle is ancient,” said Prof...