“…In addition, phosphatidylinositol-4-phosphate [PtdIns(4)P] is also synthesized on late phagosomes and may mediate phagosome maturation as well (Levin et al, 2017;Jeschke and Haas, 2018). Collectively, the acquisition of Rab7, termination of PtdIns(3)P, and the synthesis of PtdIns(3,5)P 2 and PtdIns(4)P, all drive phagosome fusion with late endosomes and lysosomes, converting the early phagosome into a phagolysosome, which then possesses lysosomal determinants like the Arf-like GTPase 8 (Arl8), lysosomal membrane proteins like lysosomal-associated membrane proteins 1 and 2 (LAMP1 and LAMP2), a myriad collection of hydrolytic enzymes, and a luminal pH <5 established by the V-ATPase (Gray and Botelho, 2017;Levin et al, 2016;Kinchen and Ravichandran, 2010;Naufer et al, 2018;Kim et al, 2014;Garg et al, 2011;Levin-Konigsberg et al, 2019;Levin et al, 2017). This ensures digestion of particulates into its primordial components like amino acids and sugars, which are exported via transporters such as SLC-36.1 (at least in Caenorhabditis elegans) or by bulk via vesicular-tubular intermediates (Mantegazza et al, 2014;Gan et al, 2019).…”