Disease relevance of bsk

• Bacterial infection also activates the JNK pathway, but the role of this pathway in the immune response has not yet been established [1].
• Remarkably, oncogenic Raf and JNK cooperate in these tumors, to induce massive hyperplasia in adjacent wild-type tissue [2].
• These results suggest that loss of Parkin function up-regulates the JNK signaling pathway, which may contribute to the vulnerability of dopaminergic neurons in Drosophila parkin mutants and perhaps autosomal recessive juvenile parkinsonism patients [3].
• Imd-mediated innate immunity is activated in response to infection by Gram-negative bacteria and leads to the activation of Jun amino-terminal kinase (JNK) and Relish, a nuclear factor-kappaB transcription factor responsible for the expression of antimicrobial peptides [4].
• Perturbation of the cell death mechanisms leads to various disorders, including neurodegenerative diseases, immunodeficiency diseases, and tumors. c-Jun N-terminal kinase (JNK) has crucial roles in the regulation of cell death in response to many stimuli [5].

High impact information on bsk

• Here we show that JNK requires Foxo to extend life span in Drosophila [6].
• TNF's main function is to stimulate inflammation by turning on gene transcription through the IKK/NFkappaB and JNK/AP-1 signaling cascades [7].
• Rescue analysis reveals different protein domain requirements in Dishevelled for the two pathways; the C-terminal DEP domain is essential to rescue planar polarity defects and induce JNK signaling [8].
• Our results indicate that distortion of the positional information determined by Dpp and Wg signalling gradients leads to activation of the JNK apoptotic pathway, and the consequent induction of cell death thereby maintains normal morphogenesis [9].
• Distortion of proximodistal information causes JNK-dependent apoptosis in Drosophila wing [9].

Biological context of bsk

• Therefore it appears that the JNK pathway is conserved and that it is involved in controlling cell morphogenesis in Drosophila [10].
• A JNK signal transduction pathway that mediates morphogenesis and an immune response in Drosophila [11].
• We show that puckered mutations result in the hyperactivation of DJNK, and that overexpression of puc mimics basket mutant phenotypes [12].
• Our data indicate that dTAK1 is not required for Relish activation, but instead is required in JNK signaling for antimicrobial peptide gene expression [13].
• BACKGROUND: During Drosophila embryogenesis, Jun kinase (JNK) signaling has been shown to play a key role in regulating the morphogenetic process of dorsal closure, which also serves as a model for epithelial sheet fusion during wound repair [14].

Anatomical context of bsk

• In addition, embryos lacking DJNK are defective in dorsal closure, a process in which the lateral epithelial cells migrate over the embryo and join at the dorsal midline [11].
• Since puc overexpression in the egg follicular epithelium mimics JNK appendages and micropyle phenotypes, it indicates a negative role of puc in their morphogenesis [15].
• We have performed a structure-function analysis of Msn in vivo in Drosophila in order to elucidate the mechanism whereby Msn regulates JNK and to determine whether msn, like dock, is required for the correct targeting of photoreceptor axons [16].
• Genetic data indicate a requirement of D-Fos and the JNK pathway for thorax closure, and a negative regulatory role of Puc [17].
• Thus, Shark regulates the JNK signaling pathway leading to Dpp expression in LE cells [18].

Associations of bsk with chemical compounds

• Exposure to endotoxic lipopolysaccharide initiates an insect immune response and leads to DJNK activation [11].
• To elucidate the signaling pathways that lead to activation of D-JNK in response to cadmium or arsenite, we employed RNA interference (RNAi) to knock down thirteen upstream regulators of D-JNK, either singly or in combinations of up to seven at a time [19].
• The mechanism of mammalian JNK activation by cadmium and sodium arsenite involves toxicant-induced oxidative stress [19].
• Furthermore, we have found that silencing of dTAB2 expression by dsRNAi inhibits JNK activation by peptidoglycans (PGN), but not by NaCl or sorbitol [20].
• In addition, glutathione modulated the effects of JNK on GST activity [21].

Enzymatic interactions of bsk

• DJNK is phosphorylated and activated by the Drosophila MAP kinase kinase HEP [11].
• Drosophila JNK and ERK phosphorylate D-Fos with overlapping, but distinct, patterns [22].

Regulatory relationships of bsk

• puckered encodes a phosphatase that mediates a feedback loop regulating JNK activity during dorsal closure in Drosophila [12].
• In Drosophila, DTRAF1 is thus a good candidate for an upstream molecule that regulates the JNK pathway by interacting with, and activating, Msn [23].
• Collectively, our findings demonstrate that DTRAF1 and DTRAF2 play pivotal roles in Drosophila development and innate immunity by differentially regulating the JNK- and the NF-kappaB-dependent signaling pathway, respectively [24].
• Overexpression of dTAK in the embryonic epidermis is sufficient to induce the transcription of the JNK target genes decapentaplegic and puckered [25].
• Taken together, our results indicate that DIAP1 may modulate cell death by regulating JNK activation through a ubiquitin#150;proteasome pathway [26].

Other interactions of bsk

• This process, dorsal closure, requires two signaling pathways: the Drosophila Jun-amino-terminal kinase (DJNK) pathway and the Dpp pathway [27].
• Dorsal closure couples JNK and dpp signaling pathways, a situation that may be conserved in vertebrate development [28].
• CKA, a novel multidomain protein, regulates the JUN N-terminal kinase signal transduction pathway in Drosophila [29].
• Consistent with this idea, expression of a dominant-negative Msn mutant protein blocks the activation of JNK by DTRAF1 [23].
• The study of mammalian signaling pathways to JNK is complicated by the significant degree of redundancy among upstream JNK regulators, especially at the level of JNK kinase kinases (JNKKK) [19].

Analytical, diagnostic and therapeutic context of bsk

• We have examined wound healing during regeneration of Drosophila wing imaginal discs fragments by confocal microscopy and assessed the role of components of the JNK pathway in this process [30].
• First identified in 1990 when intraperitoneal injection of the protein synthesis inhibitor cycloheximide activated a 54 kDa protein kinase, the JNK MAPKs have now taken on a prominent role in signal transduction [31].
• In addition to their requirement for normal development, cell culture and genetic investigations point to a role for both the JNK and p38 pathways in regulation of the immune response in the fly [32].

References