日前，在線出版的《自然—方法學》期刊上發表了一項研究成果表明，研究人員將庫存的胚胎干細胞和誘導性多能干細胞的蛋白質組進行比較，發現兩種蛋白質的表達有細微差異，新發現有助于解釋這兩類細胞在分化為特定類型細胞上的能力差異。

與胚胎干細胞類似，誘導性多能干細胞可分化為各種類型的人體細胞，這種干細胞源自成人組織，它的使用避免了用胚胎干細胞進行研究和醫學治療而出現的倫理問題。然而，問題是誘導性多能干細胞在生物學上是否*等同于胚胎干細胞?

利用以高分辨率質譜儀為基礎的蛋白質組學分析方法，Joshua Coon和同事分析了4個人類胚胎干細胞系和4個誘導性多能干細胞系的蛋白質。根據可重復的分析結果，他們在兩類干細胞的蛋白質表達上發現了可重復的差異。他們的結果顯示，誘導性多能干細胞保持了它們所源自的已分化細胞的部分特征，這種特征可能指引它們發育成特定的細胞類型。

作者將他們的數據放入一個可免費進入的新數據庫。

Proteomic and phosphoproteomic comparison of human ES and iPS cells

Combining high-mass-accuracy mass spectrometry, isobaric tagging and software for multiplexed, large-scale protein quantification, we report deep proteomic coverage of four human embryonic stem cell and four induced pluripotent stem cell lines in biological triplicate. This 24-sample comparison resulted in a very large set of identified proteins and phosphorylation sites in pluripotent cells. The statistical analysis afforded by our approach revealed subtle but reproducible differences in protein expression and protein phosphorylation between embryonic stem cells and induced pluripotent cells. Merging these results with RNA-seq analysis data, we found functionally related differences across each tier of regulation. We also introduce the Stem Cell–Omics Repository （SCOR）, a resource to collate and display quantitative information across multiple planes of measurement, including mRNA, protein and post-translational modifications.