National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM093271
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM111367
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R21GM131231
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
U24GM116788
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
U24GM116789
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
C06RR30414
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
U24GM129539
米国
Cancer Prevention and Research Institute of Texas (CPRIT)
RP120474
米国
American Heart Association
12IRG9400019
米国
National Institutes of Health/National Cancer Institute (NIH/NCI)
R01GM088745
米国
Cystic Fibrosis Foundation
JIANG15G0
米国
Welch Foundation
I-1684
米国
引用
ジャーナル: Front Mol Neurosci / 年: 2023 タイトル: Chromogranin B (CHGB) is dimorphic and responsible for dominant anion channels delivered to cell surface via regulated secretion. 著者: Gaya P Yadav / Haiyuan Wang / Joke Ouwendijk / Stephen Cross / Qiaochu Wang / Feng Qin / Paul Verkade / Michael X Zhu / Qiu-Xing Jiang / 要旨: Regulated secretion is conserved in all eukaryotes. In vertebrates granin family proteins function in all key steps of regulated secretion. Phase separation and amyloid-based storage of proteins and ...Regulated secretion is conserved in all eukaryotes. In vertebrates granin family proteins function in all key steps of regulated secretion. Phase separation and amyloid-based storage of proteins and small molecules in secretory granules require ion homeostasis to maintain their steady states, and thus need ion conductances in granule membranes. But granular ion channels are still elusive. Here we show that granule exocytosis in neuroendocrine cells delivers to cell surface dominant anion channels, to which chromogranin B (CHGB) is critical. Biochemical fractionation shows that native CHGB distributes nearly equally in soluble and membrane-bound forms, and both reconstitute highly selective anion channels in membrane. Confocal imaging resolves granular membrane components including proton pumps and CHGB in puncta on the cell surface after stimulated exocytosis. High pressure freezing immuno-EM reveals a major fraction of CHGB at granule membranes in rat pancreatic β-cells. A cryo-EM structure of bCHGB dimer of a nominal 3.5 Å resolution delineates a central pore with end openings, physically sufficient for membrane-spanning and large single channel conductance. Together our data support that CHGB-containing (CHGB+) channels are characteristic of regulated secretion, and function in granule ion homeostasis near the plasma membrane or possibly in other intracellular processes.
モデルのタイプ: OTHER 詳細: Ab initio model from cisTEM and cryoSPARC, and a reference model from angular reconstitution of a negative stain dataset.
最終 再構成
想定した対称性 - 点群: C2 (2回回転対称) / 解像度のタイプ: BY AUTHOR / 解像度: 3.5 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: cryoSPARC (ver. 3.3.2) 詳細: CryoSPARC and relion were used for independent analyses to generate similar results. 使用した粒子像数: 70000
初期 角度割当
タイプ: MAXIMUM LIKELIHOOD 詳細: Initial assignment was based on the reference model.
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD 詳細: Refinement was done in cryoSPARC and relion separately.