[show abstract][hide abstract] ABSTRACT: STAT6 plays a prominent role in adaptive immunity by transducing signals from extracellular cytokines. We now show that STAT6 is required for innate immune signaling in response to virus infection. Viruses or cytoplasmic nucleic acids trigger STING (also named MITA/ERIS) to recruit STAT6 to the endoplasmic reticulum, leading to STAT6 phosphorylation on Ser(407) by TBK1 and Tyr(641), independent of JAKs. Phosphorylated STAT6 then dimerizes and translocates to the nucleus to induce specific target genes responsible for immune cell homing. Virus-induced STAT6 activation is detected in all cell-types tested, in contrast to the cell-type specific role of STAT6 in cytokine signaling, and Stat6(-/-) mice are susceptible to virus infection. Thus, STAT6 mediates immune signaling in response to both cytokines at the plasma membrane, and virus infection at the endoplasmic reticulum.
[show abstract][hide abstract] ABSTRACT: We report here the identification and characterization of a protein, ERIS, an endoplasmic reticulum (ER) IFN stimulator, which is a strong type I IFN stimulator and plays a pivotal role in response to both non-self-cytosolic RNA and dsDNA. ERIS (also known as STING or MITA) resided exclusively on ER membrane. The ER retention/retrieval sequence RIR was found to be critical to retain the protein on ER membrane and to maintain its integrity. ERIS was dimerized on innate immune challenges. Coumermycin-induced ERIS dimerization led to strong and fast IFN induction, suggesting that dimerization of ERIS was critical for self-activation and subsequent downstream signaling.
Proceedings of the National Academy of Sciences 06/2009; 106(21):8653-8. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Soil organic matter decomposition is related to the terrestrial carbon cycle. Soil organic matter fraction responded more rapidly to land use, disturbance, vegetation type, and other factors than bulk organic matter. Organic C fraction mineralisation was assessed in seven pasture leys in erodible soil on the Loess Plateau. Leys of bromegrass (Bromus inermis) clover (Trrifolium repens ), crowtoe (Lotus corniculatus.) lucerne (Medicago sativa CV. longdong and CV. Saditi), sainfoin (Onobrychis viciaefolia) and sweet pea (Lathyrus odoratus), were established at Qingyang experimental station of Lanzhou University in 2002. Dissolved organic carbon (NPOC) showed significant difference among the pasture leys. Total carbon content (TC) for seven pasture leys ranged between 19.7-25.8 g/kg, with the highest in clover. Organic carbon content for all seven species accounted to over 50% of TC, TC and TOC/TC were significantly lower in the 5-10 cm layer then 0-5 cm layer, TOC/TC ratio declined about 20% in 5-10 cm. Legume species leys had similar labile carbon distribution in 0-5 and 5-10 cm soil layers. Bromegrss had a highest C mineralisation rate among the seven species.Grass contributed more orxdizable C ,but it was easily break down and release to CO2. It is concluded that legumes have higher potential to store more organic carbon than grass.