Morphodynamics of non-canonical autophagic structures in Neurospora crassa
- Author: mycolabadmin
- 10/17/2023
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Summary
When Neurospora crassa cells run out of carbon, they activate recycling systems to break down and reuse their own cellular components. Unlike yeast, Neurospora creates special bag-like structures called phagophores that form from the cell membrane itself rather than inside the cell. These structures can digest their contents on their own and come in surprising shapes, including doubled structures with four layers of membrane.
Background
Autophagy is a fundamental cellular recycling pathway. While well-studied in yeast and mammalian cells, autophagy in filamentous fungi like Neurospora crassa remains poorly characterized. This study investigates autophagic structures and their morphological changes during nutrient starvation.
Objective
To characterize the morphology and dynamics of autophagic structures in Neurospora crassa using high-resolution electron microscopy and tomography. To determine whether canonical autophagy machinery is required for phagophore formation in this organism.
Results
Carbon starvation triggers dual recycling pathways: massive vacuolation filling 70-80% of cytoplasmic volume, and formation of diverse phagophores and autophagosomes originating from the plasma membrane rather than the ER. Non-canonical structures include double phagophores with quadruple membranes and compound phagophores. ATG1 is not required for phagophore formation in Neurospora, unlike in yeast. Many autophagic structures appear lytic and capable of autonomous degradation.
Conclusion
Neurospora exhibits fundamentally different autophagic mechanisms from canonical yeast autophagy, including plasma membrane-derived phagophore biogenesis and lytic-autonomous organelles. These findings suggest alternative evolutionary origins for autophagic systems and implications for understanding tip growth in filamentous fungi.
- Published in:mSphere,
- Study Type:Research Study,
- Source: PMID: 37847028