A newly uncovered group of distantly related lysine methyltransferases preferentially interact with molecular chaperones to regulate their activity.
A newly uncovered group of distantly related lysine methyltransferases preferentially interact with molecular chaperones to regulate their activity.
复制标题
DOI：
10.1371/journal.pgen.1003210
复制
发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Coulombe B
中科院分区：
文献类型：
--
作者：
Cloutier P;Lavallée-Adam M;Faubert D;Blanchette M;Coulombe B
甲基化是一种翻译后修饰，可以影响蛋白质的许多特征，特别是细胞定位、周转、活性和分子相互作用。最近的全基因组分析大大扩展了人类基因编码假定甲基转移酶的列表。对蛋白质甲基转移酶的研究表明，甲基化的调节功能并不局限于表观遗传学，现在发现了许多非组蛋白底物。我们在这里提出我们的发现在一个新的家族远亲推定甲基转移酶。亲和纯化与质谱联用表明，这些蛋白明显倾向于与各种伴侣蛋白结合。根据光谱数据，我们能够在底物中确定甲基化位点，特别是KIN/Kin17的K135， HSPA8/Hsc70的K561以及其他Hsp70亚型中相应的赖氨酸残基的三甲基化，以及VCP/p97的K315。所有的修饰位点随后在体外得到证实。在VCP的情况下，METTL21D的甲基化是通过添加UBX辅助因子ASPSCR1来刺激的，我们发现它直接与甲基转移酶相互作用。当我们使用已知会导致包涵体肌病伴佩吉特骨病和额颞叶痴呆（IBMPFD）和/或家族性肌萎缩性侧索硬化症（ALS）的VCP突变体（R155H、R159G和R191Q）时，这种刺激作用就消失了。赖氨酸315位于VCP第一个ATPase/D1结构域的Walker B基序附近。我们的研究结果表明，该位点的甲基化会对其atp酶活性产生负面影响。总之，本报告揭示了蛋白甲基化作为分子伴侣调控途径的新作用，并定义了伴侣蛋白VCP的新调控机制，其解除调控可导致退行性神经肌肉疾病。甲基化，或单个或多个甲基（CH3）的转移，是发生在蛋白质上的许多翻译后修饰之一。这种修饰可以反过来影响蛋白质的许多方面，特别是细胞定位、周转、活性和分子相互作用。除了翻译后修饰外，蛋白质或蛋白质复合物的结构组织也会对其功能和稳定性产生重大影响。一组被称为“分子伴侣”的因子帮助新合成的蛋白质达到其天然构象或在生理相关状态之间交替。我们在这里提出了一个新的促进伴侣甲基化的因子家族，并表明，至少在一种情况下，这种修饰转化为底物伴侣活性的调节。我们的研究结果不仅表征了以前未知的基因产物的功能，揭示了蛋白质甲基化作为伴侣蛋白调控途径的新作用，并定义了伴侣蛋白VCP的新调控机制，其失调是神经肌肉疾病的病因，而且表明存在一种调节分子伴侣蛋白的翻译后修饰代码。进一步解密这种“伴侣密码”将有助于理解蛋白质组的功能组织是如何被编排的。
Methylation is a post-translational modification that can affect numerous features of proteins, notably cellular localization, turnover, activity, and molecular interactions. Recent genome-wide analyses have considerably extended the list of human genes encoding putative methyltransferases. Studies on protein methyltransferases have revealed that the regulatory function of methylation is not limited to epigenetics, with many non-histone substrates now being discovered. We present here our findings on a novel family of distantly related putative methyltransferases. Affinity purification coupled to mass spectrometry shows a marked preference for these proteins to associate with various chaperones. Based on the spectral data, we were able to identify methylation sites in substrates, notably trimethylation of K135 of KIN/Kin17, K561 of HSPA8/Hsc70 as well as corresponding lysine residues in other Hsp70 isoforms, and K315 of VCP/p97. All modification sites were subsequently confirmed in vitro. In the case of VCP, methylation by METTL21D was stimulated by the addition of the UBX cofactor ASPSCR1, which we show directly interacts with the methyltransferase. This stimulatory effect was lost when we used VCP mutants (R155H, R159G, and R191Q) known to cause Inclusion Body Myopathy with Paget's disease of bone and Fronto-temporal Dementia (IBMPFD) and/or familial Amyotrophic Lateral Sclerosis (ALS). Lysine 315 falls in proximity to the Walker B motif of VCP's first ATPase/D1 domain. Our results indicate that methylation of this site negatively impacts its ATPase activity. Overall, this report uncovers a new role for protein methylation as a regulatory pathway for molecular chaperones and defines a novel regulatory mechanism for the chaperone VCP, whose deregulation is causative of degenerative neuromuscular diseases. Methylation, or transfer of a single or multiple methyl groups (CH3), is one of many post-translational modifications that occur on proteins. Such modifications can, in turn, affect numerous aspects of a protein, notably cellular localization, turnover, activity, and molecular interactions. In addition to post-translational modifications, the structural organization of a protein or protein complex can also have a significant impact on its function and stability. A group of factors known as “molecular chaperones” aid newly synthesized proteins in reaching their native conformation or alternating between physiologically relevant states. We present here a new family of factors that promote methylation of chaperones and show that, at least in one case, this modification translates into a modulation in the activity of the substrate chaperone. Our results not only characterize the function of previously unknown gene products, uncover a new role for protein methylation as a regulatory pathway for chaperones, and define a novel regulatory mechanism for the chaperone VCP, whose deregulation is causative of neuromuscular diseases, but also suggest the existence of a post-translational modification code that regulates molecular chaperones. Further decrypting this “chaperone code” will help understanding how the functional organization of the proteome is orchestrated.
登录
查看更多内容
DOI：
10.1073/pnas.89.22.10915
发表时间：
1992-11-15
影响因子：
11.1
作者：
HENIKOFF, S;HENIKOFF, JG
通讯作者：
HENIKOFF, JG
影响因子：
11.4
作者：
Braun, S;Matuschewski, K;Jentsch, S
通讯作者：
Jentsch, S
影响因子：
3.3
作者：
Dalal, S;Rosser, MFN;Hanson, PI
通讯作者：
Hanson, PI
影响因子：
5.3
作者：
Jeronimo, C;Langelier, MF;Coulombe, B
通讯作者：
Coulombe, B
影响因子：
2.9
作者：
Coulombe, Benoit;Blanchette, Mathieu;Jeronimo, Celia
通讯作者：
Jeronimo, Celia