Weiss A, Littman D R
Howard Hughes Medical Institute, Department of Medicine, University of California, San Francisco 94143.
Cell. 1994 Jan 28;76(2):263-74. doi: 10.1016/0092-8674(94)90334-4.
Despite the differences in the antigens that they recognize and in the effector functions they carry out, B and T lymphocytes utilize remarkably similar signal transduction components to initiate responses. They both use oligomeric receptors that contain distinct recognition and signal transduction subunits. Antigen receptors on both cells interact with at least two distinct families of PTKs via common sequence motifs, ARAMs, in the cytoplasmic tails of their invariant chains, which have likely evolved from a common evolutionary precursor. Coreceptors appear to serve to increase the sensitivity of both of these receptor systems through events that influence ligand binding and signal transduction. The critical role of tyrosine phosphorylation of downstream signaling components, such as phospholipase C, is the net result of changes in the balance of the action of antigen receptor-regulated PTKs and PTPases. The identification of downstream effectors, including calcineurin and Ras, that regulate cellular responses, such as lymphokine gene expression, promises the future possibility of connecting the complex pathway from the plasma membrane to the nucleus in lymphocytes. Insight gained from studies of the signaling pathways downstream of TCR and BCR stimulation is likely to contribute significantly to future understanding of mechanisms responsible for lymphocyte differentiation and for the discrimination of self from nonself in developing and mature cells.
尽管B淋巴细胞和T淋巴细胞识别的抗原以及执行的效应功能存在差异，但它们利用非常相似的信号转导成分来启动反应。它们都使用包含不同识别和信号转导亚基的寡聚受体。两种细胞上的抗原受体都通过其恒定链胞质尾部的共同序列基序ARAMs与至少两个不同的PTK家族相互作用，这些基序可能源自共同的进化前体。共受体似乎通过影响配体结合和信号转导的事件来提高这两种受体系统的敏感性。下游信号成分（如磷脂酶C）酪氨酸磷酸化的关键作用是抗原受体调节的PTK和PTPase作用平衡变化的最终结果。对包括钙调神经磷酸酶和Ras在内的调节细胞反应（如淋巴因子基因表达）的下游效应器的鉴定，有望在未来将淋巴细胞中从质膜到细胞核的复杂途径联系起来。从TCR和BCR刺激下游信号通路研究中获得的见解可能会极大地促进未来对淋巴细胞分化机制以及发育中和成熟细胞中自我与非自我区分机制的理解。
