Publications by authors named "Mariya Licheva"

Autophagy is a key cellular quality control mechanism. Nutrient stress triggers bulk autophagy, which nonselectively degrades cytoplasmic material upon formation and liquid-liquid phase separation of the autophagy-related gene 1 (Atg1) complex. In contrast, selective autophagy eliminates protein aggregates, damaged organelles and other cargoes that are targeted by an autophagy receptor.

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Autophagy is initiated by the assembly of multiple autophagy-related proteins that form the phagophore assembly site where autophagosomes are formed. Atg13 is essential early in this process, and a hub of extensive phosphorylation. How these multiple phosphorylations contribute to autophagy initiation, however, is not well understood.

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Signal-sequence-dependent protein targeting is essential for the spatiotemporal organization of eukaryotic and prokaryotic cells and is facilitated by dedicated protein targeting factors such as the signal recognition particle (SRP). However, targeting signals are not exclusively contained within proteins but can also be present within mRNAs. By in vivo and in vitro assays, we show that mRNA targeting is controlled by the nucleotide content and by secondary structures within mRNAs.

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Article Synopsis
  • - Autophagy is a process where cell materials are enclosed in an autophagosome and sent for degradation, involving specific proteins called SNAREs for membrane fusion.
  • - YKT6 is an essential SNARE protein conserved across species, and changes to its function lead to defects in autophagy and reduced cell survival.
  • - The activity of YKT6 is regulated by phosphorylation from the ULK1 kinase, which is vital for proper autophagosome-lysosome fusion, impacting the overall autophagy process and cell viability.
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Invaginations of the mitochondrial inner membrane, termed cristae, are hubs for oxidative phosphorylation. The mitochondrial contact site and cristae organizing system (MICOS) and the dimeric FF-ATP synthase play important roles in controlling cristae architecture. A fraction of the MICOS core subunit Mic10 is found in association with the ATP synthase, yet it is unknown whether this interaction is of relevance for mitochondrial or cellular functions.

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Autophagosomes form at the endoplasmic reticulum in mammals, and between the vacuole and the endoplasmic reticulum in yeast. However, the roles of these sites and the mechanisms regulating autophagosome formation are incompletely understood. Vac8 is required for autophagy and recruits the Atg1 kinase complex to the vacuole.

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Mitochondria are key organelles for cellular energetics, metabolism, signaling, and quality control and have been linked to various diseases. Different views exist on the composition of the human mitochondrial proteome. We classified >8,000 proteins in mitochondrial preparations of human cells and defined a mitochondrial high-confidence proteome of >1,100 proteins (MitoCoP).

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Article Synopsis
  • Eukaryotic cells utilize post-translational modifications to enhance the functions of protein networks, crucial for various cellular processes like autophagy.
  • Autophagy, a self-degradation mechanism conserved across species, relies on the balanced activities of kinases and phosphatases for its regulation and is essential for cellular stress adaptation and homeostasis.
  • The review highlights the key roles of kinases and phosphatases in modulating core autophagy proteins and discusses the significance of phosphoregulation in facilitating the autophagy process.
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Small membrane proteins represent a largely unexplored yet abundant class of proteins in pro- and eukaryotes. They essentially consist of a single transmembrane domain and are associated with stress response mechanisms in bacteria. How these proteins are inserted into the bacterial membrane is unknown.

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Autophagy is a crucial cellular degradation and recycling pathway. During autophagy double-membrane vesicles, called autophagosomes, encapsulate cellular components and deliver their cargo to the lytic compartment for degradation. Formation of autophagosomes is regulated by the Atg1 kinase complex in yeast and the homologous ULK1 kinase complex in mammals.

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Autophagy is initiated by the formation of a phagophore assembly site (PAS), the precursor of autophagosomes. In mammals, autophagosome formation sites form throughout the cytosol in specialized subdomains of the endoplasmic reticulum (ER). In yeast, the PAS is also generated close to the ER, but always in the vicinity of the vacuole.

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Article Synopsis
  • The mitochondrial proteome relies heavily on importing proteins encoded by nuclear DNA, which usually have cleavable presequences for targeting.
  • Impaired processing of these presequences leads to an accumulation of unprocessed proteins in mitochondria that form aggregates but do not immediately result in cell death.
  • Instead, cells activate an early mitochondrial unfolded protein response (mtUPR)-like mechanism, involving the recruitment of the transcription factor Rox1, to help maintain mitochondrial function and manage the stress effectively.
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Autophagy mediates the bulk degradation of cytoplasmic material, particularly during starvation. Upon the induction of autophagy, autophagosomes form a sealed membrane around cargo, fuse with a lytic compartment, and release the cargo for degradation. The mechanism of autophagosome-vacuole fusion is poorly understood, although factors that mediate other cellular fusion events have been implicated.

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