This entry includes PROPPIN family members, which are beta-propellers that bind polyphosphoinositides, conserved from yeast to human. These are PI(3)P sensors that share a beta-propeller fold and the presence of an FRRG motif required for phosphoinositide binding and autophagy, playing a key role in autophagosome biogenesis. Four PROPPINs are known in human (WIPI1-4) and three in yeast (Atg18, Atg21 and Hvs2) [1-5]. EPG6 from C. elegans is an homologue of human WIPI4 [6].

1: Defining regulatory and phosphoinositide-binding sites in the human WIPI-1 beta-propeller responsible for autophagosomal membrane localization downstream of mTORC1 inhibition. Gaugel A, Bakula D, Hoffmann A, Proikas-Cezanne T; J Mol Signal. 2012;7:16. PMID:23088497

2: WIPI3 and WIPI4 beta-propellers are scaffolds for LKB1-AMPK-TSC signalling circuits in the control of autophagy. Bakula D, Muller AJ, Zuleger T, Takacs Z, Franz-Wachtel M, Thost AK, Brigger D, Tschan MP, Frickey T, Robenek H, Macek B, Proikas-Cezanne T; Nat Commun. 2017;8:15637. PMID:28561066

3: Two-site recognition of phosphatidylinositol 3-phosphate by PROPPINs in autophagy. Baskaran S, Ragusa MJ, Boura E, Hurley JH; Mol Cell. 2012;47:339-348. PMID:22704557

4: The autophagic membrane tether ATG2A transfers lipids between membranes. Maeda S, Otomo C, Otomo T; Elife. 2019; [Epub ahead of print] PMID:31271352

5: Structural Conservation of the Two Phosphoinositide-Binding Sites in WIPI Proteins. Liang R, Ren J, Zhang Y, Feng W; J Mol Biol. 2019;431:1494-1505. PMID:30797857

6: Autophagy-dependent ribosomal RNA degradation is essential for maintaining nucleotide homeostasis during C. elegans development. Liu Y, Zou W, Yang P, Wang L, Ma Y, Zhang H, Wang X; Elife. 2018; [Epub ahead of print] PMID:30102152