The Arabidopsis MTM1 positively regulates autophagosome and vacuole fusion
Autophagy is a conserved subcellular high-throughput degradation pathway in eukaryotes. Discarded or damaged organelles, proteins, RNA are transported into lysosomes/vacuoles in a non-selective or selective manner for degradation and recycling, maintaining cell and body homeostasis. The early and late stages of autophagosome formation, i.e., the formation of the PAS/IM and the fusion of the autophagosome with the vacuole, are regulated by a phospholipid signaling molecule, phosphatidylinositol 3-phosphate (PI3P). The generation and hydrolysis of PI3P were catalyzed by PI3KC3/VPS34 and Myotubularin (MTM) respectively. MTM mutations have been associated with a variety of neurological and muscular diseases, cancer, and cardiovascular diseases, and its most well-known function is involved in vesicles transport processes such as endocytosis and autophagy as PI3P-phosphatase. However, there are many members of the human MTM family, and their precise localization and function in the early and late stages of autophagy is still poorly understood. In contrast, the budding yeast genome encodes only one MTM, Ymr1, which regulates the fusion of autophagosomes with vacuoles. There are two MTMs in the genome of Arabidopsis, which is an ideal model organism to study the function and functional differentiation of MTMS. In order to understand the function and mechanism of MTM1 in Arabidopsis, RNA-sequencing was performed for mtm1 mutant.