SAE2: Lysates

Covalent attachment of one protein to another is one of the more prominent posttranslational modifications in respect to size and ubiquity. Ubiquitin is the most familiar of the protein modifiers and its activation and transfer to target proteins has been studied extensively. Recently, a new group of ubiquitin-like proteins has been receiving a lot of attention. SUMO, or Sentrin, is one of the most intriguing. SUMO has been implicated in the stabilization of target proteins and/or their localization to sub-cellular complexes. The conjugation of SUMO-1, SUMO-2 and SUMO-3 onto target proteins requires the concerted action of the specific E1-activating enzyme SAE1/SAE2, the E2-conjugating enzyme Ubc9, and an E3-like SUMO ligase.