RT Journal Article SR Electronic T1 Retromer retrieves the Wilson disease protein ATP7B from endolysosomes in a copper-dependent manner JF Journal of Cell Science JO J. Cell Sci. FD The Company of Biologists Ltd SP jcs246819 DO 10.1242/jcs.246819 VO 133 IS 24 A1 Das, Santanu A1 Maji, Saptarshi A1 Ruturaj, A1 Bhattacharya, Indira A1 Saha, Tanusree A1 Naskar, Nabanita A1 Gupta, Arnab YR 2020 UL http://jcs.biologists.org/content/133/24/jcs246819.abstract AB The Wilson disease protein, ATP7B maintains copper (herein referring to the Cu+ ion) homeostasis in the liver. ATP7B traffics from trans-Golgi network to endolysosomes to export excess copper. Regulation of ATP7B trafficking to and from endolysosomes is not well understood. We investigated the fate of ATP7B after copper export. At high copper levels, ATP7B traffics primarily to acidic, active hydrolase (cathepsin-B)-positive endolysosomes and, upon subsequent copper chelation, returns to the trans-Golgi network (TGN). At high copper, ATP7B colocalizes with endolysosomal markers and with a core member of retromer complex, VPS35. Knocking down VPS35 did not abrogate the copper export function of ATP7B or its copper-responsive anterograde trafficking to vesicles; rather upon subsequent copper chelation, ATP7B failed to relocalize to the TGN, which was rescued by overexpressing wild-type VPS35. Overexpressing mutants of the retromer complex-associated proteins Rab7A and COMMD1 yielded a similar non-recycling phenotype of ATP7B. At high copper, VPS35 and ATP7B are juxtaposed on the same endolysosome and form a large complex that is stabilized by in vivo photoamino acid labeling and UV-crosslinking. We demonstrate that retromer regulates endolysosome to TGN trafficking of copper transporter ATP7B in a manner that is dependent upon intracellular copper.