5jgf
From Proteopedia
Crystal structure of mApe1
Structural highlights
FunctionAMPL_YEAST Resident vacuolar enzyme that catalyzes the removal of amino acids from the N-terminus of peptides and proteins. Also acts as the major cargo protein of the cytoplasm-to-vacuole targeting (Cvt) pathway. The precursor form of aminopeptidase 1 (prApe1) assembles into dodecamers and the propeptide mediates the aggregation of dodecamers into higher multimers. The multimers are then recognized via the propeptide by their receptor ATG19, and ATG19 further interacts with ATG11, which tethers the APE1-ATG19 complex to the pre-autophagosomal structure (PAS). The cargo-receptor complex (also Cvt complex) is selectively enwrapped by a double-membrane structure termed the Cvt vesicle under vegetative growth conditions and by a similar but larger double-membrane structure termed the autophagosome under nitrogen starvation conditions. The Cvt vesicle or the autophagosome fuses with the vacuolar membrane and release its content in the vacuolar lumen. In the vacuole, prApe1 is processed into mature aminopeptidase 1 (mApe1).[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedSelective autophagy mediates the degradation of various cargoes, including protein aggregates and organelles, thereby contributing to cellular homeostasis. Cargo receptors ensure selectivity by tethering specific cargo to lipidated Atg8 at the isolation membrane. However, little is known about the structural requirements underlying receptor-mediated cargo recognition. Here, we report structural, biochemical, and cell biological analysis of the major selective cargo protein in budding yeast, aminopeptidase I (Ape1), and its complex with the receptor Atg19. The Ape1 propeptide has a trimeric coiled-coil structure, which tethers dodecameric Ape1 bodies together to form large aggregates. Atg19 disassembles the propeptide trimer and forms a 2:1 heterotrimer, which not only blankets the Ape1 aggregates but also regulates their size. These receptor activities may promote elongation of the isolation membrane along the aggregate surface, enabling sequestration of the cargo with high specificity. Structural Basis for Receptor-Mediated Selective Autophagy of Aminopeptidase I Aggregates.,Yamasaki A, Watanabe Y, Adachi W, Suzuki K, Matoba K, Kirisako H, Kumeta H, Nakatogawa H, Ohsumi Y, Inagaki F, Noda NN Cell Rep. 2016 Jun 28;16(1):19-27. doi: 10.1016/j.celrep.2016.05.066. Epub 2016, Jun 16. PMID:27320913[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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