J Cell Biol. 24 June,2019|Supp Info:http://doi.org/10.1083/jcb.201901074

The amino acid transporter SLC-36.1 cooperates with PtdIns3P 5-kinase to control phagocytic lysosome reformation

Qiwen Gan1^1,2, Xin Wang¹, Qian Zhang², Qiuyuan Yin1, Youli Jian², Yubing Liu³,Nan Xuan²,Jinglin Li¹,Junxiang Zhou²,Kai Liu², Yudong Jing²,Xiaochen Wang³,and Chonglin Yang¹.

^Abstract

Phagocytic removal of apoptotic cells involves formation, maturation,and digestion of cell corpse–containing phagosomes.The retrieval of lysosomal components following phagolysosomal digestion of cell orpses remains poorly understood.Here we reveal that the amino acid transporter SLC-36.1 is essential for lysosome reformation during cell corpse clearance in Caenorhabditis elegans embryos. Loss of slc-36.1 leads to formation of phagolysosomal vacuoles arising from cell corpse–containing phagosomes.In the absence of slc-36.1,phagosome maturation is not affected,but the retrieval of lysosomal components is inhibited.Moreover, loss of PPK-3, the C. elegans homologue of the PtdIns3P 5-kinase PIKfyve, similarly causes accumulation of phagolysosomal vacuoles that are defective in phagocytic lysosome reformation. SLC-36.1 and PPK-3 function in the same genetic pathway,and they directly interact with one another.In addition,loss of slc-36.1 and ppk-3 causes strong defects in autophagic lysosome reformation in adult animals. Our findings thus suggest that the PPK-3–SLC-36.1 axis plays a central role in both phagocytic and autophagic lysosome formation.