Annular pustular psoriasis (APP) is a rare form of pustular psoriasis with a chronic recurrent course and good prognosis. We report three cases of APP in children, two of whom were siblings. Review of the medical literature reveals that a disproportionately high percentage of cases of APP occur in children. In some cases topical therapy can clear the condition, although in severe or recalcitrant disease, systemic therapy may be necessary.

Chromosome movements during mitosis are orchestrated primarily by the interaction of spindle microtubules with the kinetochore, the site for attachment of spindle microtubules to the centromere. Kinetochore‐associated mitotic kinesin CENP‐E plays key roles in chromosome congression and spindle checkpoint satisfaction. We have recently identified and characterized syntelin, a novel selective CENP‐E inhibitor (Ding et al., 2010. Cell Res. 20, 1386‐1390). Cells treated with syntelin progress through interphase, enter mitosis normally with a bipolar spindle and lagging chromosomes around the poles. Syntelin is an allosteric inhibitor which tightens CENP‐E‐microtubule interaction by slowing inorganic phosphate release. To delineate the role of CENP‐E in reorganization of interpolar microtubules into an organized central spindle, metaphase synchronized cells were exposed to syntelin and other mitotic motor inhibitors. Syntelin does not perturb interpolar microtubule assembly but abrogates the anti‐parallel microtubule bundle formation. Real‐time image shows that CENP‐E inhibited cells undergo central spindle splitting and exhibits chromosome instability phenotypes. Interestingly, inhibition of CENP‐E did not alter the interaction between CENP‐E and PRC1 but perturbed temporal assembly of PRC1 to the midzone. Surprisingly, inhibition of CENP‐E perturbs the temporal control of PRC1 dephosphorylation which led to a persistent phosphorylation of PRC1 and an inhibition of central spindle assembly. These findings reveal a previously uncharacterized role of CENP‐E motor in temporal control of central spindle assembly. Grant Funding Source: DK56292; CA164133

GPR15 is a chemoattractant receptor that facilitates colon homing of regulatory and effector CD4 + T cells in health and colitis. The molecular mechanisms that control GPR15 expression are not fully known. Here we report the presence of two highly conserved aryl hydrocarbon receptor (AHR) binding sequences in a 3′ enhancer of GPR15, leading us to investigate AHR function in regulating GPR15 expression. Using luciferase reporter assays, we show that AHR activation increased GPR15 expression and requires both the AHR binding sites. Consistent with a transcriptional regulatory role, treatment with AHR agonists induce GPR15 expression on human CD4 + T cells. Using AHR-deficient mice, we demonstrate that the lack of AHR signaling drastically reduces GPR15 expression on effector/memory and Foxp3 + CD4 + T cells. In mixed bone marrow chimeras of AHR-deficient and wildtype cells, GPR15 expression was similarly diminished on AHR-deficient CD4 + effector/memory and regulatory T cells in the colon and small intestine. Furthermore, administration of AHR agonists upregulated GPR15 expression on CD4 + effector/memory T cells and increased their homing capability, especially to the colon. Collectively, our studies reveal a novel function of the AHR in regulation of GPR15 expression and increased colon trafficking of CD4 + T cells expressing GPR15.

Diacylglycerol kinases (DGKs) play important roles in restraining diacylglycerol (DAG)‐mediated signaling. Within the DGK family, the ζ isoform appears to be the most important isoform in T cells for controlling their development and function. DGKζ has been demonstrated to regulate T cell maturation, activation, anergy, effector/memory differentiation, defense against microbial infection, and antitumor immunity. Given its critical functions, DGKζ function should be tightly regulated to ensure proper signal transduction; however, mechanisms that control DGKζ function are still poorly understood. We report here that DGKζ dynamically translocates from the cytosol into the nuclei in T cells after TCR stimulation. In mice, DGKζ mutant defective in nuclear localization displayed enhanced ability to inhibit TCR‐induced DAG‐mediated signaling in primary T cells, maturation of conventional αβT and iNKT cells, and activation of peripheral T cells compared with WT DGKζ. Our study reveals for the first time nuclear sequestration of DGKζ as a negative control mechanism to spatially restrain it from terminating DAG mediated signaling in T cells. Our data suggest that manipulation of DGKζ nucleus‐cytosol shuttling as a novel strategy to modulate DGKζ activity and immune responses for treatment of autoimmune diseases and cancer.