泛素蛋白酶体途径及其对植物生长发育的调控

泛素蛋白酶体途径主要由泛素活化酶、泛素结合酶、泛素蛋白连接酶和26S蛋白酶体组成。泛素活化酶首先激活泛素分子，然后把泛素转移到泛素结合酶上。泛素结合酶结合泛素蛋白连接酶并把泛素转移到底物蛋白上使底物泛素化，或把泛素转移到泛素蛋白连接酶再使底物泛素化。泛素化的蛋白通常通过26S蛋白酶体进行降解。初步的研究结果表明，植物生长发育的很多方面受泛素蛋白酶体介导的蛋白降解途径的调控。

The Ubiquitin-Proteosome Pathway and Plant Development

The ubiquitin/26S proteosome pathway mainly consists of ubiquitin activating enzyme (E1), ubiquitin conjugating enzyme (E2), ubiquitin protein ligase (E3), and 26S proteasome. In the initial reaction, E1 activates the Ub by coupling ATP hydrolysis, the activated Ub is then transferred to an E2. The E2 either transfers ubiquitin directly to the E3 in the case of HECT E3s or binds the E3 and transfers the ubiquitin to the substrate. Polyubiquinated proteins are eventually degraded by the 26S proteasome. In plants, regulated protein degradation by the ubiquitin/26S proteosome contributes significantly to development by affecting a wide range of processes, including hormone signaling, photomorphogenesis, and flower development.