Truttmann Matthias C, Zheng Xu, Hanke Leo, Damon Jadyn R, Grootveld Monique, Krakowiak Joanna, Pincus David, Ploegh Hidde L
Whitehead Institute for Biomedical Research, Cambridge, MA 02142.
Whitehead Institute for Biomedical Research, Cambridge, MA 02142;
Proc Natl Acad Sci U S A. 2017 Jan 10;114(2):E152-E160. doi: 10.1073/pnas.1619234114. Epub 2016 Dec 28.
Protein AMPylation is a conserved posttranslational modification with emerging roles in endoplasmic reticulum homeostasis. However, the range of substrates and cell biological consequences of AMPylation remain poorly defined. We expressed human and Caenorhabditis elegans AMPylation enzymes-huntingtin yeast-interacting protein E (HYPE) and filamentation-induced by cyclic AMP (FIC)-1, respectively-in Saccharomyces cerevisiae, a eukaryote that lacks endogenous protein AMPylation. Expression of HYPE and FIC-1 in yeast induced a strong cytoplasmic Hsf1-mediated heat shock response, accompanied by attenuation of protein translation, massive protein aggregation, growth arrest, and lethality. Overexpression of Ssa2, a cytosolic heat shock protein (Hsp)70, was sufficient to partially rescue growth. In human cell lines, overexpression of active HYPE similarly induced protein aggregation and the HSF1-dependent heat shock response. Excessive AMPylation also abolished HSP70-dependent influenza virus replication. Our findings suggest a mode of Hsp70 inactivation by AMPylation and point toward a role for protein AMPylation in the regulation of cellular protein homeostasis beyond the endoplasmic reticulum.
蛋白质腺苷酸化是一种保守的翻译后修饰，在内质网稳态中发挥着新出现的作用。然而，腺苷酸化的底物范围和细胞生物学后果仍不清楚。我们分别在缺乏内源性蛋白质腺苷酸化的真核生物酿酒酵母中表达了人类和秀丽隐杆线虫的腺苷酸化酶——亨廷顿蛋白酵母相互作用蛋白E（HYPE）和环磷酸腺苷诱导的丝状化蛋白1（FIC-1）。HYPE和FIC-1在酵母中的表达诱导了强烈的细胞质热休克因子1（Hsf1）介导的热休克反应，同时伴随着蛋白质翻译的减弱、大量蛋白质聚集、生长停滞和致死性。细胞质热休克蛋白（Hsp）70的Ssa2过表达足以部分挽救生长。在人类细胞系中，活性HYPE的过表达同样诱导了蛋白质聚集和HSF1依赖性热休克反应。过量的腺苷酸化还消除了HSP70依赖性流感病毒的复制。我们的研究结果表明了一种通过腺苷酸化使Hsp70失活的模式，并指出蛋白质腺苷酸化在内质网以外的细胞蛋白质稳态调节中发挥作用。
