Autophagy reportsPub Date : 2025-01-01Epub Date: 2025-02-19DOI: 10.1080/27694127.2025.2467454
Nimna V Wijewantha, Taras Y Nazarko
{"title":"Glycogen is a neutral cargo of bulk autophagy in <i>Komagataella phaffii</i>.","authors":"Nimna V Wijewantha, Taras Y Nazarko","doi":"10.1080/27694127.2025.2467454","DOIUrl":"10.1080/27694127.2025.2467454","url":null,"abstract":"<p><p>Glycogen is a primary cellular energy store in numerous eukaryotes. Its biosynthesis is a main strategy to cope with forthcoming starvation. During starvation, glycogen is processed in the cytosol or delivered for degradation to animal lysosomes or yeast vacuoles by macroautophagy (hereafter autophagy). However, the mechanism of glycogen autophagy is poorly understood, especially in the heart and skeletal muscles that suffer from the lysosomal glycogen accumulation in Pompe disease. We recently developed the <i>Komagataella phaffii</i> yeast as a simple model to study glycogen autophagy and found that this pathway proceeds non-selectively. However, studies in <i>Saccharomyces cerevisiae</i> proposed glycogen as a non-preferred cargo of bulk autophagy. In our latest study with new fluorescent reporters for glycogen, we clarified cargo properties of <i>K. phaffii</i> glycogen. Both homologous and heterologous markers of glycogen are delivered to the vacuole and degraded with efficiencies that are independent of glycogen, suggesting that glycogen is a neutral cargo of bulk autophagy. This work provides insights into the evolutionary diversity of glycogen autophagy in yeasts with implications for understanding this process in complex eukaryotes.</p>","PeriodicalId":72341,"journal":{"name":"Autophagy reports","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11864558/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143588427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Autophagy reportsPub Date : 2025-01-01Epub Date: 2025-03-10DOI: 10.1080/27694127.2025.2464376
Charleen T Chu
{"title":"The Role of Autophagy in Excitotoxicity, Synaptic Mitochondrial Stress and Neurodegeneration.","authors":"Charleen T Chu","doi":"10.1080/27694127.2025.2464376","DOIUrl":"10.1080/27694127.2025.2464376","url":null,"abstract":"<p><p>Brain and nervous system functions depend upon maintaining the integrity of synaptic structures over the lifetime. Autophagy, a key homeostatic quality control system, plays a central role not only in neuronal development and survival/cell death, but also in regulating synaptic activity and plasticity. Glutamate is the major excitatory neurotransmitter that activates downstream targets, with a key role in learning and memory. However, an excess of glutamatergic stimulation is pathological in stroke, epilepsy and neurodegeneration, triggering excitotoxic cell death or a sublethal process of excitatory mitochondrial calcium toxicity (EMT) that triggers dendritic retraction. Markers of autophagy and mitophagy are often elevated following excitatory neuronal injuries, with the potential to influence cell death or neurodegenerative outcomes of these injuries. Interestingly, leucine-rich repeat kinase 2 (LRRK2) and PTEN-induced kinase 1 (PINK1), two kinases linked to autophagy, mitophagy and Parkinson disease, play important roles in regulating mitochondrial calcium handling, synaptic density and function, and maturation of dendritic spines. Mutations in LRRK2, PINK1, or proteins linked to Alzheimer's disease perturb mitochondrial calcium handling to sensitize neurons to excitatory injury. While autophagy and mitophagy can play both protective and harmful roles, studies in various excitotoxicity and stroke models often implicate autophagy in a pathogenic role. Understanding the role of autophagic degradation in regulating synaptic loss and cell death following excitatory neuronal injuries has important therapeutic implications for both acute and chronic neurological disorders.</p>","PeriodicalId":72341,"journal":{"name":"Autophagy reports","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11921967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143797196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}