Solution structure of the autophagy-related protein LC3C reveals a polyproline II motif on a mobile tether with phosphorylation site.

(Macro-)autophagy is a compartmental degradation pathway conserved from yeast to mammals. The yeast protein Atg8 mediates membrane tethering/hemifusion and cargo recruitment and is essential for autophagy. The human MAP1LC3/GABARAP family proteins show high sequence identity with Atg8, but MAP1LC3C is distinguished by a conspicuous amino-terminal extension with unknown functional significance.

Solid-State NMR H-N-(C)-H and H-N-C-C 3D/4D Correlation Experiments for Resonance Assignment of Large Proteins.

Solid-state NMR spectroscopy can provide insight into protein structure and dynamics at the atomic level without inherent protein size limitations. However, a major hurdle to studying large proteins by solid-state NMR spectroscopy is related to spectral complexity and resonance overlap, which increase with molecular weight and severely hamper the assignment process. Here the use of two sets of experiments is shown to expand the tool kit of H-detected assignment approaches, which correlate a given amide pair either to the two adjacent CO-CA pairs (4D hCOCANH/hCOCAcoNH), or to the amide H of the neighboring residue (3D HcocaNH/HcacoNH, which can be extended to 5D).

Sequence-specific 1H, 15N, and 13C resonance assignments of the autophagy-related protein LC3C.

Autophagy is a versatile catabolic pathway for lysosomal degradation of cytoplasmic material. While the phenomenological and molecular characteristics of autophagic non-selective (bulk) decomposition have been investigated for decades, the focus of interest is increasingly shifting towards the selective mechanisms of autophagy. Both, selective as well as bulk autophagy critically depend on ubiquitin-like modifiers belonging to the Atg8 (autophagy-related 8) protein family.