Department of Cell Biology and Development, Biomedical Science Institute, São Paulo, SP, Brazil.
AAPS J. 2010 Dec;12(4):608-16. doi: 10.1208/s12248-010-9224-y. Epub 2010 Jul 28.
Cells produce and use peptides in distinctive ways. In the present report, using isotope labeling plus semi-quantitative mass spectrometry, we evaluated the intracellular peptide profile of TAP1/β2m⁻(/)⁻ (transporter associated with antigen-processing 1/ß2 microglobulin) double-knockout mice and compared it with that of C57BL/6 wild-type animals. Overall, 92 distinctive peptides were identified, and most were shown to have a similar concentration in both mouse strains. However, some peptides showed a modest increase or decrease (~2-fold), whereas a glycine-rich peptide derived from the C-terminal of neurogranin (KGPGPGGPGGAGGARGGAGGGPSGD) showed a substantial increase (6-fold) in TAP1/β2m⁻(/)⁻ mice. Thus, TAP1 and β2microglobulin have a small influence on the peptide profile of neuronal tissue, suggesting that the presence of peptides derived from intracellular proteins in neuronal tissue is not associated with antigens of the class I major histocompatibility complex. Therefore, it is possible that these intracellular peptides play a physiological role.
细胞以独特的方式产生和利用肽。在本报告中，我们使用同位素标记加半定量质谱法，评估了 TAP1/β2m⁻(/)⁻（抗原加工相关转运蛋白 1/β2 微球蛋白）双敲除小鼠的细胞内肽谱，并将其与 C57BL/6 野生型动物进行了比较。总的来说，鉴定出了 92 种独特的肽，并且大多数肽在两种小鼠品系中的浓度相似。然而，一些肽显示出适度的增加或减少（~2 倍），而源自神经颗粒蛋白 C 端的富含甘氨酸的肽（KGPGPGGPGGAGGARGGAGGGPSGD）在 TAP1/β2m⁻(/)⁻小鼠中显著增加（6 倍）。因此，TAP1 和 β2 微球蛋白对神经元组织的肽谱影响很小，这表明神经元组织中源自细胞内蛋白的肽的存在与 I 类主要组织相容性复合物的抗原无关。因此，这些细胞内肽可能发挥着生理作用。
