Rossman Jeremy S, Stoicheva Natalia G, Langel Felicia D, Patterson George H, Lippincott-Schwartz Jennifer, Schaefer Brian C
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
Mol Biol Cell. 2006 May;17(5):2166-76. doi: 10.1091/mbc.e05-10-0985. Epub 2006 Feb 22.
Stimulation of the T-cell receptor (TCR) results in the activation of several transcription factors, including NF-kappaB, that are crucial for T-cell proliferation and gain of effector functions. On TCR engagement, several proteins within the TCR-directed NF-kappaB signaling pathway undergo dynamic spatial redistribution, but the significance of these redistribution events is largely unknown. We have previously described TCR-induced cytoplasmic structures called POLKADOTS (punctate and oligomeric killing or activating domains transducing signals) that are enriched in the NF-kappaB signaling intermediate, Bcl10. We now show that these structures are formed only under conditions that promote efficient NF-kappaB activation. Furthermore, POLKADOTS formation is dependent on functional domains of specific NF-kappaB signal transducers. Through use of a photoactivatable GFP, we demonstrate that POLKADOTS contain both a highly stable and a rapidly equilibrating protein component. FRET analyses show that POLKADOTS are sites of enriched interactions between Bcl10 and partner signaling proteins. These observations strongly suggest that POLKADOTS are focal sites of dynamic information exchange between cytosolic intermediates in the process of TCR activation of NF-kappaB.
T细胞受体（TCR）的刺激会导致多种转录因子的激活，包括NF-κB，这些转录因子对于T细胞增殖和效应功能的获得至关重要。在TCR参与时，TCR导向的NF-κB信号通路中的几种蛋白质会发生动态空间重新分布，但这些重新分布事件的意义在很大程度上尚不清楚。我们之前描述了TCR诱导的细胞质结构，称为POLKADOTS（点状和寡聚化杀伤或激活结构域转导信号），其富含NF-κB信号中间体Bcl10。我们现在表明，这些结构仅在促进有效NF-κB激活的条件下形成。此外，POLKADOTS的形成依赖于特定NF-κB信号转导分子的功能结构域。通过使用光活化绿色荧光蛋白，我们证明POLKADOTS包含一个高度稳定和一个快速平衡的蛋白质成分。荧光共振能量转移分析表明，POLKADOTS是Bcl10与伙伴信号蛋白之间富集相互作用的位点。这些观察结果强烈表明，POLKADOTS是NF-κB的TCR激活过程中细胞质中间体之间动态信息交换的焦点位点。
