ALLO-1a is a ubiquitin-binding adaptor for allophagy in Caenorhabditis elegans.
Norizuki, T., Kushida, Y., Sekimoto, T., Sasaki, T., Yamano, K., Matsuda, N., Sasaki, R., Noda, N.N., Sato, K., Sato, M.(2025) J Cell Sci 
- PubMed: 41234204 
- DOI: https://doi.org/10.1242/jcs.264252
- Primary Citation of Related Structures:  
9VBS - PubMed Abstract: 
In the nematode Caenorhabditis elegans, sperm-derived mitochondria and membranous organelles (MOs) are selectively degraded by autophagy in embryos in a process termed allophagy. For this process, ALLO-1 functions as an autophagy adaptor. The allo-1 gene encodes two splice isoforms, ALLO-1a and b, which have different C-terminal sequences and are predominantly targeted to MOs and paternal mitochondria, respectively. However, the mechanism by which ALLO-1 targets the paternal organelles remains unknown. In this study, X-ray crystallography analysis reveals that the C-terminal region of ALLO-1a forms a parallel coiled-coil structure. In addition, Alphafold-Multimer predicts that this region directly interacts with ubiquitin. We showed that ALLO-1a interacts with K48- and K63-linked polyubiquitin in vitro and found that the 355th Asp residue of ALLO-1a at the predicted interface with ubiquitin is important for its ubiquitin binding in vitro and also for its MO-targeting and MO degradation in embryos. These results suggest that ubiquitin is a marker for the recognition of MOs by the autophagy machinery in C. elegans embryos.
- Laboratory of Molecular Membrane Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan.
Organizational Affiliation: 
















