Reciprocal regulation of chaperone-mediated autophagy and the circadian clock

Abstract

Circadian rhythms align physiological functions with the light-dark cycle through oscillatory changes in the abundance of proteins in the clock transcriptional program. Timely removal of these proteins by different proteolytic systems is essential to circadian strength and adaptability. Here we show a functional interplay between the circadian clock and chaperone-mediated autophagy (CMA), whereby CMA contributes to the rhythmic removal of clock machinery proteins (selective chronophagy) and to the circadian remodeling of a subset of the cellular proteome. Disruption of this autophagic pathway in vivo leads to temporal shifts and amplitude changes of the clock-dependent transcriptional waves and fragmented circadian patterns, resembling those in sleep disorders and aging. Conversely, loss of the circadian clock abolishes the rhythmicity of CMA, leading to pronounced changes in the CMA-dependent cellular proteome. Disruption of this circadian clock/CMA axis may be responsible for both pathways malfunctioning in aging and for the subsequently pronounced proteostasis defect.

Defining the age-dependent and tissue-specific circadian transcriptome in male mice

“…In the Aged, Tfeb is no longer circadian and the autophagy cluster is centered toward the middle of the rest phase (Figure 5D). Recent studies have implicated changes in the timing of autophagy as a contributor to aging in flies and mice (Juste et al, 2021; Ulgherait et al, 2021). The REGs in the Old muscle were largely unimodal, peaking at activity offset.…”

Hsp40 overexpression in pacemaker neurons delays circadian dysfunction in a Drosophila model of Huntington's disease

“…The converse, i.e. proteostasis affecting the molecular clock via post-translational modifications and autophagy, is also prevalent ( Mehra et al, 2009 ; Stojkovic et al, 2014 ; Toledo et al, 2018 ; Juste et al, 2021 ). However, very few studies have assessed the role of Hsps in circadian maintenance and its deterioration in NDs, especially in animals.…”

The lysosomal proteome of senescent cells contributes to the senescence secretome

“…Induction of chaperone-mediated autophagy (CMA) can be monitored with a KFERQ-photo-switchable (PS)-Dendra fluorescent reporter as an increase in fluorescent puncta when this reporter is delivered to lysosomes via CMA (Caballero et al, 2018;Dong et al, 2020Dong et al, , 2021Juste et al, 2021;Koga et al, 2011).…”

“…SK-MEL-103 cells were transduced with a lentivirus carrying the photo-switchable KFERQ-PS-Dendra2 CMA reporter, a brighter modified version of the original reporters (Caballero et al, 2018;Dong et al, 2020Dong et al, , 2021Juste et al, 2021;Koga et al, 2011) to measure CMA, or with a lentivirus carrying a tandem fluorescent LC3 construct (mCherry-GFP-LC3; Kimura et al, 2007) To acquire images from the 96-well plates, we used a high-content microscope (Operetta System, Perkin Elmer) and quantification was performed with the manufacturer's software in a minimum of 800 cells (approx. 9 fields).…”