Coordinated regulation of cell migration, cytokine maturation and apoptosis is critical in inflammatory responses. Caspases, a family of cysteine proteases, are known to regulate cytokine maturation and apoptosis. Here, we show that caspase-11, a mammalian pro-inflammatory caspase, regulates cell migration during inflammation. Caspase-11-deficient lymphocytes exhibit a cell-autonomous migration defect in vitro and in vivo. We demonstrate that caspase-11 interacts physically and functionally with actin interacting protein 1 (Aip1), an activator of cofilin-mediated actin depolymerization. The caspase-recruitment domain (CARD) of caspase-11 interacts with the carboxy-terminal WD40 propeller domain of Aip1 to promote cofilin-mediated actin depolymerization. Cells with Aip1 or caspase-11 deficiency exhibit defects in actin dynamics. Using in vitro actin depolymerization assays, we found that caspase-11 and Aip1 work cooperatively to promote cofilin-mediated actin depolymerization. These data demonstrate a novel cell autonomous caspase-mediated mechanism that regulates actin dynamics and mammalian cell migration distinct from the receptor mediated Rho-Rac-Cdc42 pathway.

Summary Vps34 (vacuolar protein sorting 34) complexes, the class III PtdIns3 kinase, specifically phosphorylate the D3-position of PtdIns to produce PtdIns3P. Vps34 is involved in the control of multiple key intracellular membrane trafficking pathways including endocytic sorting and autophagy. In mammalian cells, Vps34 interacts with Beclin 1, an orthologue of Atg6 in yeast, to regulate the production of PtdIns3P and autophagy. We show that Vps34 is phosphorylated on Thr159 by Cdk1, which negatively regulates its interaction with Beclin1 during mitosis. Cdk5/p25, a neuronal cdk shown to play a role in Alzheimer’s disease, can also phosphorylate Thr159 of Vps34. Phosphorylation of Vps34 on Thr159 inhibits its interaction with Beclin 1. We propose that phosphorylation of Thr159 in Vps34 is a key regulatory mechanism that controls the class III PtdIns3 kinase activity in cell cycle progression, development and human diseases including neurodegeneration and cancers.

Caspase-1 and caspase-11 are proinflammatory caspases that regulate cytokine production and leukocyte migration during pathogen infection. In an attempt to identify new intracellular regulators of caspase-11, we found that Flightless-I, a member of the gelsolin superfamily of actin-remodeling proteins, interacts and regulates both caspase-11 and caspase-1. Flightless-I targets caspase-11 to the Triton X-100–insoluble cytoskeleton fraction and the cell leading edge. In addition, Flightless-I inhibits caspase-1 activation and caspase-1–mediated interleukine-1β (IL-1β) maturation. The physiological relevance of these findings is supported by the opposing effects of Flightless-I overexpression and knockdown on caspase-1 activity and IL-1β maturation. Our results suggest that Flightless-I may be a bona fide caspase-1 inhibitor that acts through a mechanism similar to that of cytokine response modifier A, a potent caspase-1 inhibitor from the cowpox virus. Our study provides a new mechanism controlling the localization and activation of proinflammatory caspases.

The antiepileptic drug carbamazepine (CBZ) is one of the most frequently detected human pharmaceuticals in wastewater effluents and biosolids. Soil is a primary environmental compartment receiving CBZ through wastewater irrigation and biosolid application. In this study, we explored the transformation of CBZ to biologically active intermediates in soil. Both (14)C labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to track transformation kinetics and identify major degradation intermediates. Through 120 days of incubation under aerobic conditions, mineralization of CBZ did not exceed 2% of the spiked rate in different soils. Amendment of biosolids further suppressed mineralization. The fraction of non-extractable (i.e., bound) residue also remained negligible (<5%). On the other hand, CBZ was transformed to a range of degradation intermediates, including 10,11-dihydro-10-hydroxycarbamazepine, carbamazepine-10,11-epoxide, acridone-N-carbaldehyde, 4-aldehyde-9-acridone, and acridine, of which acridone-N-carbaldehyde was formed in a large fraction and appeared to be recalcitrant to further degradation. Electrocyclization, ring cleavage, hydrogen shift, carbonylation, and decarbonylation contributed to CBZ transformative reactions in soil, producing biologically active products. The persistence of the parent compound and formation of incomplete intermediates suggest that CBZ has a high risk for off-site transport from soil, such as accumulation into plants and contamination of groundwater.

The microphthalmia-associated transcription factor (MITF) is essential for melanocyte development. Mutation-induced MAPK pathway activation is common in melanoma and induces MITF phosphorylation, ubiquitination, and proteolysis. Little is known about the enzymes involved in MITF ubiquitination/deubiquitination. Here we report the identification of a deubiquitinating enzyme, named ubiquitin-specific protease 13 (USP13) that appears to be responsible for MITF deubiquitination, utilizing a short hairpin RNA library against known deubiquitinating enzymes. Through deubiquitination, USP13 stabilizes and upregulates MITF protein levels. Conversely, suppression of USP13 (through knockdown) leads to dramatic loss of MITF protein, but not messenger RNA. Through its effects on MITF deubiquitination, USP13 was observed to modulate expression of MITF downstream target genes and, thereby, to be essential for melanoma growth in soft agar and in nude mice. These observations suggest that as a potentially drugable protease, USP13 might be a viable therapeutic target for melanoma.

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The coumarin-based probe Cu(II)-COT1 was successfully developed for the detection of HNO on the basis of the reduction reaction. In addition, highly selective "turn on" type fluorogenic behavior upon the addition of Angeli's salt (Na(2)N(2)O(3)) was also applied to bioimaging in A375 cells.

Many pharmaceutical and personal care products (PPCPs) and endocrine-disrupting chemicals (EDCs) are present in reclaimed water, leading to concerns of human health risks from the consumption of food crops irrigated with reclaimed water. This study evaluated the potential for plant uptake and accumulation of four commonly occurring PPCP/EDCs, i.e., bisphenol A (BPA), diclofenac sodium (DCL), naproxen (NPX), and 4-nonylphenol (NP), by lettuce (Lactuca sativa) and collards (Brassica oleracea) in hydroponic culture, using 14C-labeled compounds. In both plant species, plant accumulation followed the order of BPA > NP > DCL > NPX and accumulation in roots was much greater than in leaves and stems. Concentrations of 14C-PPCP/EDCs in plant tissues ranged from 0.22±0.03 to 927± 213 ng/g, but nearly all 14C-residue was non-extractable. PPCP/EDCs, particularly BPA and NP, were also extensively transformed in the nutrient solution. Dietary uptake of these PPCP/EDCs by humans was predicted to be negligible.