PERspectives on circadian cell biology

Philosophical Transactions of the Royal Society B Biological Sciences, Год журнала: 2025, Номер 380(1918)

Опубликована: Янв. 23, 2025

Daily rhythms in the activities of PERIOD proteins are critical to temporal regulation mammalian physiology. While molecular partners and genetic circuits that allow effect auto-repression regulate transcriptional programmes increasingly well understood, comprehension time-resolved mechanisms conduct this daily dance is incomplete. Here, we consider character controversies central clock protein with a focus on its intrinsically disordered nature. This article part Theo Murphy meeting issue ‘Circadian infection immunity’.

Язык: Английский

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Evolution of canonical circadian clock genes underlies unique sleep strategies of marine mammals for secondary aquatic adaptation

PLoS Genetics, Год журнала: 2025, Номер 21(3), С. e1011598 - e1011598

Опубликована: Март 18, 2025

To satisfy the needs of sleeping underwater, marine mammals, including cetaceans, sirenians, and pinnipeds, have evolved an unusual form sleep, known as unihemispheric slow-wave sleep (USWS), in which one brain hemisphere is asleep while other awake. All aquatic cetaceans only USWS without rapid eye movement (REM) whereas sirenians amphibious pinnipeds display both bihemispheric (BSWS) USWS, well REM sleep. However, molecular genetic changes underlying remain unknown. The present study investigated evolution eight canonical circadian genes found that positive selection occurred mainly within cetacean lineages. Furthermore, convergent was observed lineages with at three clock genes. Remarkably, vitro assays showed cetacean-specific mutations increased nuclear localization zebrafish clocka , enhanced transcriptional activation activity Clocka Bmal1a. In vivo transcriptome analysis overexpression mutant ( -mut) caused upregulation wakefulness-promoting glutamatergic differential expression multiple associated regulation. contrast, GABAergic cholinergic pathways, play important roles promoting were downregulated bmal1a -mut-overexpressing zebrafish. Concordantly, time overexpressing -mut significantly less than wild-type genes, respectively. These findings support our hypothesis may adaptively to enhance regulation ability relating and, turn, contribute formation USWS.

Язык: Английский

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Disordered clock protein interactions and charge blocks turn an hourglass into a persistent circadian oscillator

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Апрель 25, 2024

Abstract Organismal physiology is widely regulated by the molecular circadian clock, a feedback loop composed of protein complexes whose members are enriched in intrinsically disordered regions. These regions can mediate protein-protein interactions via SLiMs, but contribution these to clock had not been elucidated. To determine functionality regions, we applied synthetic peptide microarray approach FRQ Neurospora crassa . We identified residues required for FRQ’s interaction with its partner FRH, mutation which demonstrated FRH necessary persistent oscillations repression transcriptional activity. Additionally, an enrichment binding peptides net positive charge. found that positively charged occurred significant “blocks” within amino acid sequence and ablation one blocks affected both core timing physiological output. Finally, charge clusters were commonly shared feature repressive proteins. Overall, our study suggests mechanistic purpose yielded insights into arm roles function.

Язык: Английский

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Phosphorylation, disorder, and phase separation govern the behavior of Frequency in the fungal circadian clock

eLife, Год журнала: 2023, Номер 12

Опубликована: Ноя. 24, 2023

Circadian clocks are composed of transcription-translation negative feedback loops that pace rhythms gene expression to the diurnal cycle. In filamentous fungus Neurospora crassa, proteins Frequency (FRQ), FRQ-interacting RNA helicase (FRH), and Casein-Kinase I (CK1) form FFC complex represses genes activated by white-collar (WCC). FRQ orchestrates key molecular interactions clock despite containing little predicted tertiary structure. Spin labeling pulse-dipolar electron spin resonance spectroscopy provide domain-specific structural insights into 989-residue intrinsically disordered FFC. contains a compact core associates organizes FRH CK1 coordinate their roles in WCC repression. phosphorylation increases conformational flexibility alters oligomeric state, but changes structure dynamics non-uniform. Full-length undergoes liquid-liquid phase separation (LLPS) sequester influence enzymatic activity. Although favors LLPS, LLPS feeds back reduce at higher temperatures. Live imaging hyphae reveals foci characteristic condensates near nuclear periphery. Analogous repressor organisms share position-specific sequence identity with FRQ; yet, they contain amino acid compositions promote LLPS. Hence, condensate formation may be conserved feature eukaryotic clocks.

Язык: Английский

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Methylxanthines Modulate Circadian Period Length Independently of the Action of Phosphodiesterase

Microbiology Spectrum, Год журнала: 2023, Номер 11(4)

Опубликована: Июнь 5, 2023

In Neurospora crassa, caffeine and other methylxanthines are known to inhibit phosphodiesterase (PDE) activity, leading augmented cAMP levels. this organism, it has also been shown that the addition of these drugs significantly lengthens circadian period, as seen by conidiation rhythms. Utilizing in vivo bioluminescence reporters, pharmacological inhibitors, analogs, we revisited effect role signaling clockworks. We observed caffeine, like all tested methylxanthines, led significant period lengthening, visualized with both core-clock transcriptional translational reporters. Remarkably, phenotype is still when activity genetically or chemically (via 3-isobutyl-1-methylxanthine) abrogated. Likewise, exert a several pathway mutants, including adenylate cyclase (cr-1) protein kinase A (PKA) (Δpkac-1) suggesting lead phenotypes through mechanisms different from canonical PDE-cAMP-PKA axis. Thus, study highlights strong impact on Neurospora, albeit exact somehow remain elusive. IMPORTANCE Evidence diverse organisms show causes changes clock, causing lengthening. The fungus crassa no exception; here, such theophylline, aminophylline cause lengthening concentration-dependent manner. Although expected were able genetic means their effects mechanism. Moreover, our results indicate increases levels PKA do not therefore part underlying methylxanthine. These set stage for future analyses dissecting molecular which dramatically modify period.

Язык: Английский

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Circadian regulation of physiology by disordered protein-protein interactions

Current Opinion in Structural Biology, Год журнала: 2023, Номер 84, С. 102743 - 102743

Опубликована: Дек. 13, 2023

Язык: Английский

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