Dynamics and architecture of the NRBF2-containing phosphatidylinositol 3-kinase complex I of autophagy

作者：Young Lindsey N; Cho Kelvin; Lawrence Rosalie; Zoncu Roberto; Hurley James H

来源：Proceedings of the National Academy of Sciences, 2016, 113(29): 8224-8229.

DOI：10.1073/pnas.1603650113

• hydrogen-deuterium exchange
• electron microscopy
• allostery

The class III phosphatidylinositol 3-kinase complex I (PI3KC3-C1) is central to autophagy initiation. We previously reported the V-shaped architecture of the four-subunit version of PI3KC3-C1 consisting of VPS (vacuolar protein sorting) 34, VPS15, BECN1 (Beclin 1), and ATG (autophagy-related) 14. Here we show that a putative fifth subunit, nuclear receptor binding factor 2 (NRBF2), is a tightly bound component of the complex that profoundly affects its activity and architecture. NRBF2 enhances the lipid kinase activity of the catalytic subunit, VPS34, by roughly 10-fold. We used hydrogen-deuterium exchange coupled to mass spectrometry and negative-stain electron microscopy to map NRBF2 to the base of the V-shaped complex. NRBF2 interacts primarily with the N termini of ATG14 and BECN1. We show that NRBF2 is a homodimer and drives the dimerization of the larger PI3KC3-C1 complex, with implications for the higher-order organization of the preautophagosomal structure.

• 出版日期2016-7-19