Differential regulation of EGF receptor internalization and degradation by multiubiquitination within the kinase domain
Differential regulation of EGF receptor internalization and degradation by multiubiquitination within the kinase domain
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DOI：
10.1016/j.molcel.2006.02.018
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发表时间：
2006-03-17
期刊：
影响因子：
16
通讯作者：
Sorkin, A
中科院分区：
文献类型：
--
作者：
Huang, FT;Kirkpatrick, D;Sorkin, A
表皮生长因子受体（EGFR）的泛素化被认为在调节其定位和稳定性方面起着关键作用。为了阐明EGFR泛素化的作用，使用串联质谱法来鉴定EGFR的激酶结构域内的六个不同的赖氨酸残基，其可以在生长因子刺激后与泛素缀合。这些赖氨酸残基的取代，导致整体泛素化显着下降，但保留正常的酪氨酸磷酸化的EGFR。泛素化缺陷型EGFR突变体在其周转率方面表现出严重缺陷，但其内化率与野生型受体相当。最后，定量质谱法证明，超过50%的EGFR结合的泛素是聚泛素链的形式，主要通过Lys63连接。总之，这些数据提供了EGFR泛素化在受体靶向溶酶体中的作用的直接证据，并暗示Lys63连接的多聚泛素链在此分选过程中。
Ubiquitination of the EGF receptor (EGFR) is believed to play a critical role in regulating both its localization and its stability. To elucidate the role of EGFR ubiquitination, tandem mass spectrometry was used to identify six distinct lysine residues within the kinase domain of the EGFR, which can be conjugated to ubiquitin following growth factor stimulation. Substitution of these lysine residues with arginines resulted in a dramatic decrease in overall ubiquitination but preserved normal tyrosine phosphorylation of EGFR. Ubiquitination-deficient EGFR mutants displayed a severe defect in their turnover rates but were internalized at rates comparable to those of wild-type receptors. Finally, quantitative mass spectrometry demonstrated that more than 50% of all EGFR bound ubiquitin was in the form of polyubiquitin chains, primarily linked through Lys63. Taken together, these data provide direct evidence for the role of EGFR ubiquitination in receptor targeting to the lysosome and implicate Lys63-linked polyubiquitin chains in this sorting process.