The 2011 Nobel Prize in Physiology or Medicine has been awarded to Bruce A. Beutler, Jules A. Hoffmann and the late Ralph M. Steinman. Beutler and Hoffmann were honored for "their discoveries concerning the activation of innate immunity," while Steinman was awarded the other half of the prize for "his discovery of the dendritic cell and its role in adaptive immunity." Their achievements are lauded in this month's editorial (p 1127

The kinase LRK2 in a complex with the large noncoding RNA NRON negatively regulates the transcription factor NFAT, as reported by Lenardo and colleagues (p 1063; and News and Views by Jabri and Barreiro, p 1029). Overexpression of LRK2 abrogates the nuclear translocation of NFAT1-GFP induced by ionomycin. Nuclei are counterstained with Hoechst 33342. Original image by Zhihua Liu. Artwork by Lewis Long.

DDX41, a member of the DExD/H-box helicase family, senses viral DNA and triggers type 1 interferon responses in a manner dependent on the adaptor STING, as reported by Liu and colleagues (p 959; News and Views by Barber, p 929). DDX41 mutants that lack the STING-binding DEADc domain (green dots) fail to associate with cytoplasmic STING (red); DAPI stains the nucleus (blue). Original image by Musheng Bao. Artwork by Lewis Long.

The chemokine receptor CCR7 is crucial for successful lymph node homing of afferent lymph—derived immune cells, as reported by Förster and colleagues (p 879). The original image shows a three-dimensional reconstruction of serial lymph node sections from mice that received intralymphatic injection of wild-type (green) and CCR7-deficient (red) dendritic cells; blue, counterstaining with antibody to immunoglobulin D. Original image by Katharina Hoffmann and Asolina Braun. Artwork by Lewis Long.

NF-κB is the key transcription factor that orchestrates inflammatory responses and contributes to the development of the immune system. This month's focus features a series of specially commissioned review articles to mark the 25th anniversary of the discovery of NF-κB. http://www.nature.com/ni/focus/NF-kB/index.html Artwork by Lewis Long.

In T cells, three distinct protein kinase C (PKC) isozymes function sequentially to induce polarization of the microtubule-organizing center toward the immunological synapse, as reported by Huse and colleagues (p 647). Original image shows the PKC substrate Marcksl1 associated with the plasma membrane (red; total internal reflection fluorescence microscopy) and the microtubule-organizing center (blue; epifluorescence microscopy) in two T cells. Marcksl1 is depleted from the plasma membrane by PKC phosphorylation. Original image by Xin Liu. Artwork by Lewis Long.

Memory is a key feature of the central nervous system that enables an organism to adapt and respond appropriately to a stimulus-rich environment. In the same way, the ability of the adaptive immune system to 'remember' past encounters with pathogens allows the host to survive in an antigenically hostile environment. This month's focus features a series of specially commissioned reviews of the cellular and molecular bases of immunological memory (http://www.nature.com/ni/focus/immunologicalmemory/). Artwork by Lewis Long.

Secretion of the chemokine CXCL12 and its deposition on the apical surface of primary human bone marrow stromal cells is dependent on cell-cell contact, as described by Schajnovitz and colleagues (p 391; see also News and Views by Milsom and Trumpp, p 377). Original fluorescence microscopy image shows the presentation of functional CXCL12 (green) by contacting primary human bone marrow stromal cells in vitro. Original image by Amir Schajnovitz. Artwork by Lewis Long.

In response to activation, regulatory T cells undergo a differentiation program that enables them to produce interleukin 10 and access nonlymphoid tissues, as shown by Kallies and colleagues (p 304; see also News and Views by Ohkura and Sakaguchi, p 283). The original image is from the animation "Fighting Infection by Clonal Selection," created at the Walter and Eliza Hall Institute by Etsuko Uno and Drew Berry, and shows lymphocyte populations of distinct antigen specificities (various colors) in the lymph node. Artwork by Lewis Long.

Symbiotic microbes spontaneously induce the cytidine deaminase AID in germinal center B cells to diversify the intestinal immunoglobulin A repertoire by somatic hypermutation. Honjo and colleagues show that a knock-in mutation of the gene encoding AID resulting in a somatic hypermutation- specific defect causes compromised mucosal defense. The original fluorescent microscopy image shows germinal center B cells (yellow) and nonactivated B cells (red) in Peyer's patches. Original image by Min Wei. Artwork by Lewis Long.

Eosinophils are an essential cellular component of the plasma cell survival niche in the bone marrow, as described by Berek and colleagues (p 151; see also News and Views by Brink p 115). Original immunofluorescence stain of a bone marrow section shows colocalization of eosinophils (red) and plasma cells (green). Nuclei are counterstained with the DNAintercalating dye DAPI (blue). Original image by Van Trung Chu and Sandra Zehentmeier. Artwork by Lewis Long.

Members of the PARP superfamily regulate many biological and pathological cellular responses. Takaoka and colleagues identify the PARP-13 shorter isoform ZAPS as a potent stimulator of RNA helicase RIG-I-mediated signaling during viral infection (p 37; News and Views by Gale Jr, p 11). The original pseudocolor-based image of corrected FRET shows an interaction between YFP-tagged ZAPS and CFP-tagged RIG-I. Original image by Fumi Kashigi and Yusuke Ohba. Artwork by Lewis Long.