Macrophages swallow damaged mitochondria through microautophagy

Takeshi NODA, Lu SHIOU-LING
Center for Frontier Oral Science
Department of Oral Cellular Biology

Research group found that macrophages use microautophagy, mediated by Rab32-positive lysosome-related organelles, to directly engulf damaged mitochondria and other organelles. This was discovered to be independent of macroautophagy. Key factors in this process include Rab32 GTPase, PI(3,5)P2, ubiquitination, and p62/SQSTM1. By clearing mitochondria, microautophagy promotes metabolic reprogramming toward glycolysis, supporting M1 macrophage polarization. Loss of Rab32/38 disrupts this process, highlighting microautophagy’s role in regulating macrophage function.

The article, “Evidence for Mitochondria in macrophages are destroyed by microautophagy,” has been published in Journal Nature Communications at DOI: https://doi.org/10.1038/s41467-025-63531-x