Mikroautofágia

Mikroautofágia is a cellular process by which the cell engulfs portions of its own cytoplasm in a non-selective manner. This process involves the invagination or pino-cytotic uptake of cytoplasmic material directly into the lysosome or vacuole. Unlike macroautophagy, which involves the formation of a double-membraned autophagosome, microautophagy is a more direct mechanism of degradation.

The engulfed cytoplasmic material is then broken down by lysosomal enzymes. This process is thought to play a role in cellular housekeeping, removing damaged or unneeded components. It can also be important during starvation conditions, providing the cell with essential nutrients. Microautophagy is a continuous and basal process, meaning it occurs at a low level even under normal conditions.

Several types of microautophagy have been described, including: piecemeal microautophagy of the nucleus (PMN), where parts of the nucleus are engulfed; cytoplasm to vacuole targeting (CVT) pathway, which is a distinct process but shares some similarities; and lipid droplet microautophagy, where lipid droplets are directly sequestered by the vacuole. The precise mechanisms and regulation of microautophagy are still areas of active research.