Direct Interaction of Chivosazole F with Actin Elicits Cell Responses Similar to Latrunculin A but Distinct from Chondramide

The
microbial metabolite Chivosazole F has been described to affect
the cytoskeleton and to inhibit actin polymerization in vitro. Applying orthogonal genomic and proteomics approaches, we now show
for the first time that Chivosazole F exerts its effect by directly
interacting with actin and demonstrate the cellular impact of Chivosazole
F in an unbiased, genome-wide context in yeast and in mammalian cells.
Furthermore, mutation-based resistance mapping identifies two SNPs
located in the putative Chivosazole F binding site of actin. Comparing
chemogenomic profiles and responses to the Chivosazole F-resistant
SNPs shows a partially conserved mechanism of action for Chivosazole
F and Latrunculin A, but clear divergence from Chondramide. In addition,
C14orf80 is an evolutionarily highly conserved ORF, lacking any functional
annotation. As editing of C14orf80 leads to Chivosazole F hyper-resistance,
we propose a function for this gene product in counteracting perturbation
of actin filaments.

微生物代谢物奇沃索霉素F（Chivosazole F）已被报道可影响细胞骨架，并在体外抑制肌动蛋白聚合。本研究采用正交基因组学与蛋白质组学联用方法，首次证实奇沃索霉素F可通过直接与肌动蛋白相互作用发挥其生物学效应，并在酵母与哺乳动物细胞的无偏全基因组研究背景下，阐明了奇沃索霉素F的细胞效应。进一步通过基于突变的耐药性定位分析，我们鉴定出两个位于肌动蛋白假定奇沃索霉素F结合位点内的单核苷酸多态性（Single Nucleotide Polymorphisms, SNPs）。通过对比化学基因组谱特征以及针对奇沃索霉素F耐药性SNPs的细胞响应模式，结果显示奇沃索霉素F与拉春库林A（Latrunculin A）的作用机制存在部分保守性，但与软骨霉素（Chondramide）则呈现显著差异。此外，C14orf80是一个进化上高度保守的开放阅读框（Open Reading Frame, ORF），目前尚无任何功能注释。由于对C14orf80进行基因编辑可使细胞对奇沃索霉素F产生高耐药性，我们据此提出该基因编码的蛋白产物在拮抗肌动蛋白丝的扰动过程中发挥功能。