Positional proteomics reveals differences in N-terminal proteoform stability.
Positional proteomics reveals differences in N-terminal proteoform stability.
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DOI：
10.15252/msb.20156662
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发表时间：
2016-02-18
影响因子：
9.9
通讯作者：
Van Damme P
中科院分区：
文献类型：
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作者：
Gawron D;Ndah E;Gevaert K;Van Damme P
为了了解替代翻译起始对蛋白质组的影响，我们使用定位蛋白质组学和核糖体分析进行了蛋白质组范围内的蛋白质周转研究，以区分单个基因的N端蛋白质形态。通过将脉冲SILAC与N端COFRADIC结合，我们监测了1,941个人类N端蛋白质形式的稳定性，其中包括147个N端蛋白质形式对，这些蛋白质形式源于引发剂蛋氨酸的替代翻译起始、替代剪接或不完全加工。N端截断的蛋白质形式比典型的蛋白质形式少，并且经常表现出改变的稳定性，可能归因于个体蛋白质特征，包括内在紊乱，但与N端氨基酸身份或截断长度无关。我们发现，蛋氨酸氨基肽酶去除引发剂蛋氨酸会降低加工后的蛋白质形态的稳定性，而N端乙酰化的易感性似乎并不影响蛋白质的周转率。综上所述，我们的研究结果揭示了N端蛋白质形态之间蛋白质稳定性的差异，并指出了替代翻译起始和协同翻译起始物蛋氨酸去除在蛋白质组动态平衡的整体调节中的作用，仅次于替代剪接。
To understand the impact of alternative translation initiation on a proteome, we performed a proteome‐wide study on protein turnover using positional proteomics and ribosome profiling to distinguish between N‐terminal proteoforms of individual genes. By combining pulsed SILAC with N‐terminal COFRADIC, we monitored the stability of 1,941 human N‐terminal proteoforms, including 147 N‐terminal proteoform pairs that originate from alternative translation initiation, alternative splicing or incomplete processing of the initiator methionine. N‐terminally truncated proteoforms were less abundant than canonical proteoforms and often displayed altered stabilities, likely attributed to individual protein characteristics, including intrinsic disorder, but independent of N‐terminal amino acid identity or truncation length. We discovered that the removal of initiator methionine by methionine aminopeptidases reduced the stability of processed proteoforms, while susceptibility for N‐terminal acetylation did not seem to influence protein turnover rates. Taken together, our findings reveal differences in protein stability between N‐terminal proteoforms and point to a role for alternative translation initiation and co‐translational initiator methionine removal, next to alternative splicing, in the overall regulation of proteome homeostasis.