Department of Proteomics and Signal Transduction, Max-Planck Institute for Biochemistry, Martinsried D-82152, Germany.
Mol Cell. 2010 Aug 27;39(4):641-52. doi: 10.1016/j.molcel.2010.07.026.
Reversible protein modification by small ubiquitin-like modifiers (SUMOs) is critical for eukaryotic life. Mass spectrometry-based proteomics has proven effective at identifying hundreds of potential SUMO target proteins. However, direct identification of SUMO acceptor lysines in complex samples by mass spectrometry is still very challenging. We have developed a generic method for the identification of SUMO acceptor lysines in target proteins. We have identified 103 SUMO-2 acceptor lysines in endogenous target proteins. Of these acceptor lysines, 76 are situated in the SUMOylation consensus site [VILMFPC]KxE. Interestingly, eight sites fit the inverted SUMOylation consensus motif [ED]xK[VILFP]. In addition, we found direct mass spectrometric evidence for crosstalk between SUMOylation and phosphorylation with a preferred spacer between the SUMOylated lysine and the phosphorylated serine of four residues. In 16 proteins we identified a hydrophobic cluster SUMOylation motif (HCSM). SUMO conjugation of RanGAP1 and ZBTB1 via HCSMs is remarkably efficient.
小分子泛素样修饰物（SUMO）对真核生物的生命至关重要。基于质谱的蛋白质组学已被证明能有效地鉴定数百种潜在的 SUMO 靶蛋白。然而，通过质谱直接鉴定复杂样品中的 SUMO 受体赖氨酸仍然极具挑战性。我们开发了一种通用的鉴定靶蛋白中 SUMO 受体赖氨酸的方法。我们在内源性靶蛋白中鉴定了 103 个 SUMO-2 受体赖氨酸。在这些受体赖氨酸中，76 个位于 SUMOylation 保守位点[VILMFPC]KxE 中。有趣的是，有 8 个位点符合反向 SUMOylation 保守基序[ED]xK[VILFP]。此外，我们发现 SUMOylation 和磷酸化之间存在直接的质谱证据，SUMO 化赖氨酸和磷酸化丝氨酸之间有 4 个残基的优先间隔。在 16 种蛋白质中，我们鉴定出一个疏水性簇 SUMOylation 基序（HCSM）。通过 HCSM 对 RanGAP1 和 ZBTB1 的 SUMO 缀合非常有效。
