TEX264 is a major receptor for mammalian reticulophagy.

The endoplasmic reticulum (ER) is the main site of cellular protein and calcium homeostasis, as well as lipid synthesis in eukaryotic cells. Reticulophagy is the selective clearance and degradation of ER components and membranes by the cellular autophagy machinery. Recently, 2 groups (the laboratories of Noboru Mizushima and Wade Harper) independently identified the previously uncharacterized protein TEX264 (testis expressed gene 264) as a major receptor for selective reticulophagy in mammalian cells. Here we highlight and integrate the major findings of their recent work. AIM: Atg8-interacting motif; AP-MS: affinity purification-mass spectrometry; ATL3: atlastin GTPase 3; Baf A: bafilomycin A; CCPG1: cell cycle progression 1; CRISPR: clustered regularly interspaced short palindromic repeats; GABARAP: gamma-aminobutyric acid receptor associated protein; GFP: green fluorescent protein; GyrI: gyrase inhibitor; IDR: intrinsically disordered region; IP: immunoprecipitation; KO: knockout; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MS: mass spectrometry; MTOR: mechanistic target of rapamycin kinase; RB1CC1/FIP200: RB1-inducible coiled-coil 1; RFP: red fluorescent protein; RNAi: RNA interference; RTN3: reticulon 3; RTN3L: long isoform of RTN3; siRNA: small interfering RNA; SARS: selective autophagy receptors; ss: signal sequence; TEM: transmission electron microscopy, TEX264: testis expressed gene 264; TMT: tandem mass tagging.