Department of Molecular Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Section of Structural Biology, Department of Infectious Diseases, Imperial College London, London, UK.
EMBO J. 2021 May 3;40(9):e105853. doi: 10.15252/embj.2020105853. Epub 2021 Feb 8.
p97ATPase-mediated membrane fusion is required for the biogenesis of the Golgi complex. p97 and its cofactor p47 function in soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) priming, but the tethering complex for p97/p47-mediated membrane fusion remains unknown. In this study, we identified formiminotransferase cyclodeaminase (FTCD) as a novel p47-binding protein. FTCD mainly localizes to the Golgi complex and binds to either p47 or p97 via its association with their polyglutamate motifs. FTCD functions in p97/p47-mediated Golgi reassembly at mitosis in vivo and in vitro via its binding to p47 and to p97. We also showed that FTCD, p47, and p97 form a big FTCD-p97/p47-FTCD tethering complex. In vivo tethering assay revealed that FTCD that was designed to localize to mitochondria caused mitochondria aggregation at mitosis by forming a complex with endogenous p97 and p47, which support a role for FTCD in tethering biological membranes in cooperation with the p97/p47 complex. Therefore, FTCD is thought to act as a tethering factor by forming the FTCD-p97/p47-FTCD complex in p97/p47-mediated Golgi membrane fusion.
p97ATPase 介导的膜融合对于高尔基体复合物的生物发生是必需的。p97 和其辅助因子 p47 可在可溶性 N-乙基马来酰亚胺敏感因子（NSF）附着蛋白受体（SNARE）引发中发挥作用，但 p97/p47 介导的膜融合的连接复合物仍然未知。在这项研究中，我们鉴定了氨基甲酰磷酸合成酶 1, 线粒体（CPS1, mt），是一种新的 p47 结合蛋白。FTCD 主要定位于高尔基体，并通过与多聚谷氨酸基序的结合与 p47 或 p97 结合。FTCD 通过与 p47 和 p97 结合，在体内和体外的有丝分裂中 p97/p47 介导的高尔基体重组装中发挥作用。我们还表明，FTCD、p47 和 p97 形成一个大的 FTCD-p97/p47-FTCD 连接复合物。体内连接测定表明，设计定位于线粒体的 FTCD 通过与内源性 p97 和 p47 形成复合物，在有丝分裂时引起线粒体聚集，这支持了 FTCD 通过与 p97/p47 复合物合作在生物膜连接中发挥作用的作用。因此，FTCD 被认为通过形成 FTCD-p97/p47-FTCD 复合物在 p97/p47 介导的高尔基体膜融合中充当连接因子。
