Structure of the C-terminal dimerization domain of Atg38Structure of the C-terminal dimerization domain of Atg38

Structural highlights

5kc1 is a 12 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.2Å
Ligands:, , , , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

ATG38_YEAST Autophagy-related protein required for cytoplasm to vacuole transport (Cvt) and autophagy as a part of the autophagy-specific VPS34 PI3-kinase complex I. This complex is essential to recruit the ATG8-phosphatidylinositol conjugate and the ATG12-ATG5 conjugate to the pre-autophagosomal structure. ATG38 is required for the integrity of the active PI3-kinase complex I by maintaining an association between VPS15-VPS34 and ATG1P-VPS30 subcomplexes.[1]

Publication Abstract from PubMed

The phosphatidylinositol 3-kinase Vps34 is part of several protein complexes. The structural organization of heterotetrameric complexes is starting to emerge, but little is known about organization of additional accessory subunits that interact with these assemblies. Combining hydrogen-deuterium exchange mass spectrometry (HDX-MS), X-ray crystallography and electron microscopy (EM), we have characterized Atg38 and its human ortholog NRBF2, accessory components of complex I consisting of Vps15-Vps34-Vps30/Atg6-Atg14 (yeast) and PIK3R4/VPS15-PIK3C3/VPS34-BECN1/Beclin 1-ATG14 (human). HDX-MS shows that Atg38 binds the Vps30-Atg14 subcomplex of complex I, using mainly its N-terminal MIT domain and bridges the coiled-coil I regions of Atg14 and Vps30 in the base of complex I. The Atg38 C-terminal domain is important for localization to the phagophore assembly site (PAS) and homodimerization. Our 2.2 A resolution crystal structure of the Atg38 C-terminal homodimerization domain shows 2 segments of alpha-helices assembling into a mushroom-like asymmetric homodimer with a 4-helix cap and a parallel coiled-coil stalk. One Atg38 homodimer engages a single complex I. This is in sharp contrast to human NRBF2, which also forms a homodimer, but this homodimer can bridge 2 complex I assemblies.

Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex.,Ohashi Y, Soler N, Garcia Ortegon M, Zhang L, Kirsten ML, Perisic O, Masson GR, Burke JE, Jakobi AJ, Apostolakis AA, Johnson CM, Ohashi M, Ktistakis NT, Sachse C, Williams RL Autophagy. 2016 Sep 14:0. PMID:27630019[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Araki Y, Ku WC, Akioka M, May AI, Hayashi Y, Arisaka F, Ishihama Y, Ohsumi Y. Atg38 is required for autophagy-specific phosphatidylinositol 3-kinase complex integrity. J Cell Biol. 2013 Oct 28;203(2):299-313. doi: 10.1083/jcb.201304123. PMID:24165940 doi:http://dx.doi.org/10.1083/jcb.201304123
  2. Ohashi Y, Soler N, Garcia Ortegon M, Zhang L, Kirsten ML, Perisic O, Masson GR, Burke JE, Jakobi AJ, Apostolakis AA, Johnson CM, Ohashi M, Ktistakis NT, Sachse C, Williams RL. Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex. Autophagy. 2016 Sep 14:0. PMID:27630019 doi:http://dx.doi.org/10.1080/15548627.2016.1226736

5kc1, resolution 2.20Å

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