Proteomics Facility, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India.
Proteomics Clin Appl. 2014 Feb;8(1-2):19-34. doi: 10.1002/prca.201300068.
Both enzymatic and nonenzymatic PTMs of proteins involve chemical modifications. Some of these modifications are prerequisite for the normal functioning of cell, while other chemical modifications render the proteins as "neo-self" antigens, which are recognized as "non-self" leading to aberrant cellular and humoral immune responses. However, these modifications could be a secondary effect of autoimmune diseases, as in the case of type I diabetes, hyperglycemia leads to protein glycation. The enigma of chemical modifications and immune response is akin to the "chick-and-egg" paradox. Nevertheless, chemical modifications regulate immune response. In some of the well-known autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis, chemically modified proteins act as autoantigens forming immune complexes. In some instances, chemical modifications are also involved in regulating immune response during pathogen infection. Further, the usefulness of proteomic analysis of immune complexes is briefly discussed.
蛋白质的酶促和非酶促 PTM 都涉及化学修饰。这些修饰中的一些是细胞正常功能的前提，而其他化学修饰则使蛋白质成为“新自身”抗原，被识别为“非自身”，导致异常的细胞和体液免疫反应。然而，这些修饰可能是自身免疫性疾病的继发效应，例如 1 型糖尿病，高血糖导致蛋白质糖化。化学修饰和免疫反应的谜团类似于“先有鸡还是先有蛋”的悖论。然而，化学修饰可以调节免疫反应。在一些著名的自身免疫性疾病中，如类风湿关节炎、系统性红斑狼疮和多发性硬化症，化学修饰的蛋白质作为自身抗原形成免疫复合物。在某些情况下，化学修饰也参与调节病原体感染期间的免疫反应。此外，简要讨论了免疫复合物的蛋白质组学分析的有用性。
