Fig. 4: Model of micronucleophagy regulation by macronucleophagy.
From: Macronucleophagy maintains cell viability under nitrogen starvation by modulating micronucleophagy
In wild-type cells starved for a nitrogen source, Atg39-mediated macronucleophagy is induced, leading to the degradation of nuclear NVJ proteins such as Nvj1, and micronucleophagy is maintained at a moderate level (left). If Atg39-mediated macronucleophagy is impaired, Nvj1-mediated micronucleophagy is strongly enhanced (right). This micronucleophagy enhancement can be explained in part by the accumulation of nuclear NVJ proteins (macronucleophagy substrates) and may also involve nuclear flattening and NVJ expansion caused by the absence of macronucleophagy. Enhanced micronucleophagy results in the excessive transport of various nuclear materials to the vacuole, and the removal of specific components or the disruption of normal nuclear processes is thought to lead to cell death in Atg39-mediated macronucleophagy-defective mutants under nitrogen starvation.
