From the Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 029, Canada.
the Department of Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada, and.
J Biol Chem. 2018 May 4;293(18):6736-6750. doi: 10.1074/jbc.M117.816272. Epub 2018 Mar 12.
Adipogenesis involves a complex signaling network requiring strict temporal and spatial organization of effector molecules. Molecular scaffolds, such as 14-3-3 proteins, facilitate such organization, and we have previously identified 14-3-3ζ as an essential scaffold in adipocyte differentiation. The interactome of 14-3-3ζ is large and diverse, and it is possible that novel adipogenic factors may be present within it, but this possibility has not yet been tested. Herein, we generated mouse embryonic fibroblasts from mice overexpressing a tandem affinity purification (TAP) epitope-tagged 14-3-3ζ molecule. After inducing adipogenesis, TAP-14-3-3ζ complexes were purified, followed by MS analysis to determine the 14-3-3ζ interactome. We observed more than 100 proteins that were unique to adipocyte differentiation, 56 of which were novel interacting partners. Among these, we were able to identify previously established regulators of adipogenesis ( Ptrf/Cavin1) within the 14-3-3ζ interactome, confirming the utility of this approach to detect adipogenic factors. We found that proteins related to RNA metabolism, processing, and splicing were enriched in the interactome. Analysis of transcriptomic data revealed that 14-3-3ζ depletion in 3T3-L1 cells affected alternative splicing of mRNA during adipocyte differentiation. siRNA-mediated depletion of RNA-splicing factors within the 14-3-3ζ interactome, that is, of Hnrpf, Hnrpk, Ddx6, and Sfpq, revealed that they have essential roles in adipogenesis and in the alternative splicing of and the adipogenesis-associated gene In summary, we have identified novel adipogenic factors within the 14-3-3ζ interactome. Further characterization of additional proteins within the 14-3-3ζ interactome may help identify novel targets to block obesity-associated expansion of adipose tissues.
脂肪生成涉及一个复杂的信号网络,需要效应分子的严格时空组织。分子支架,如 14-3-3 蛋白,促进了这种组织,我们之前已经确定 14-3-3ζ 是脂肪细胞分化中的必需支架。14-3-3ζ 的互作组很大且多样化,并且其中可能存在新的脂肪生成因子,但这种可能性尚未得到验证。在此,我们从过表达串联亲和纯化 (TAP) 表位标记 14-3-3ζ 分子的小鼠胚胎成纤维细胞中生成了小鼠。在诱导脂肪生成后,TAP-14-3-3ζ 复合物被纯化,然后进行 MS 分析以确定 14-3-3ζ 互作组。我们观察到超过 100 种独特于脂肪细胞分化的蛋白质,其中 56 种是新的相互作用伙伴。在这些蛋白质中,我们能够在 14-3-3ζ 互作组中识别先前建立的脂肪生成调节剂(Ptrf/Cavin1),证实了这种方法用于检测脂肪生成因子的有效性。我们发现与 RNA 代谢、加工和剪接相关的蛋白质在互作组中富集。转录组数据分析表明,3T3-L1 细胞中 14-3-3ζ 的耗竭会影响脂肪细胞分化过程中 mRNA 的可变剪接。14-3-3ζ 互作组中的 RNA 剪接因子(Hnrpf、Hnrpk、Ddx6 和 Sfpq)的 siRNA 介导耗竭揭示了它们在脂肪生成和脂肪生成相关基因的可变剪接中具有重要作用。综上所述,我们已经在 14-3-3ζ 互作组中鉴定出了新的脂肪生成因子。对 14-3-3ζ 互作组中更多蛋白质的进一步表征可能有助于确定阻止肥胖相关脂肪组织扩张的新靶点。