Two distinct signalling cascades target the NF-κB regulatory factor c-IAP1 for degradation

c-IAP1 (cellular inhibitor of apoptosis 1) has recently emerged as a negative regulator of the non-canonical NF-κB (nuclear factor κB) signalling cascade. Whereas synthetic IAP inhibitors have been shown to trigger the autoubiquitination and degradation of c-IAP1, less is known about the physiological mechanisms by which c-IAP1 stability is regulated. In the present paper, we describe two distinct cellular processes that lead to the targeted loss of c-IAP1. Recruitment of a TRAF2 (tumour necrosis factor receptor-associated factor 2)–c-IAP1 complex to the cytoplasmic domain of the Hodgkin's/anaplastic large-cell lymphoma-associated receptor, CD30, leads to the targeting and degradation of the TRAF2–c-IAP1 heterodimer through a mechanism requiring the RING (really interesting new gene) domain of TRAF2, but not c-IAP1. In contrast, the induced autoubiquitination of c-IAP1 by IAP antagonists causes the selective loss of c-IAP1, but not TRAF2, thereby releasing TRAF2. Thus c-IAP1 can be targeted for degradation by two distinct processes, revealing the critical importance of this molecule as a regulator of numerous intracellular signalling cascades

Investigation and validation of a novel Endo GIA stapler for canine lung lobectomies

The objectives of this study were to validate the 2.0 mm Endo GIA stapler for lung lobectomies and to compare procedural time and air leakage incidence with suture ligation. Sixteen canine cadavers, 18 to 27 kg, were randomly assigned to undergo lung lobectomy of the right middle lung lobe through intercostal thoracotomy, after which suture ligation or the 2.0 mm Endo GIA stapler was used. Procedural time was recorded. Following the lobectomy, the thoracic cavity was filled with fluid. Positive pressure ventilation was used to hold pressure at 20 cm HO for 5 minutes. The bronchus was assessed for air leakage as evidenced by visualization of gas bubbles and the ability to maintain positive pressure. Procedural time and air leakage incidence were compared between groups. By these assessments, the 2.0 mm Endo GIA stapler was successful for lung lobectomies in all cadavers. There was no significant difference (t = -0.856, = 0.407) in body weight by procedure assignment. Procedural time was significantly shorter ( \u3c 0.0001) using the Endo GIA stapler compared to suture ligation. There was no significant correlation ( = 0.044, = 0.873) between body weight and procedural time. There were no incidents of air leakage in either group. The 2.0 mm Endo GIA stapler may be used as an alternative device for lung lobectomies in canine cadavers. Smaller staples may provide more complete compression of hilar vessels and bronchi, resulting in reduced hemorrhage, air leakage, and thoracic contamination in cases with infection or neoplasia

Apoptosis-Inducing Factor Is a Target for Ubiquitination through Interaction with XIAP▿ †

X-linked inhibitor of apoptosis (XIAP) is an inhibitor of apoptotic cell death that protects cells by caspase-dependent and independent mechanisms. In a screen for molecules that participate with XIAP in regulating cellular activities, we identified apoptosis-inducing factor (AIF) as an XIAP binding protein. Baculoviral IAP repeat 2 of XIAP is sufficient for the XIAP/AIF interaction, which is disrupted by Smac/DIABLO. In healthy cells, mature human AIF lacks only the first 54 amino acids, differing significantly from the apoptotic form, which lacks the first 102 amino-terminal residues. Fluorescence complementation and immunoprecipitation experiments revealed that XIAP interacts with both AIF forms. AIF was found to be a target of XIAP-mediated ubiquitination under both normal and apoptotic conditions, and an E3 ubiquitin ligase-deficient XIAP variant displayed a more robust interaction with AIF. Expression of either XIAP or AIF attenuated both basal and antimycin A-stimulated levels of reactive oxygen species (ROS), and when XIAP and AIF were expressed in combination, a cumulative decrease in ROS was observed. These results identify AIF as a new XIAP binding partner and indicate a role for XIAP in regulating cellular ROS

Relationship of osteoarthritic changes in the index and contralateral stifles.

<p>(<b>A</b>) Bivariate histogram of radiographic synovial effusion grade in index and contralateral stifles. (<b>B</b>) Bivariate histogram of osteophytosis grade in index and contralateral stifles. Severity of osteophytosis (S_R = 0.39, <i>p</i><0.0005), but not synovial effusion (S_R = 0.17, <i>p</i> = 0.13) in the index and contralateral stifles were correlated.</p

Confounding factors for case exclusion.

<p><b>Note</b>: 55 dogs in total were excluded during case filtering because of confounding clinical factors. More than one confounding factor was found in some dogs.</p><p>Confounding factors for case exclusion.</p

Time to contralateral cranial cruciate ligament rupture stratified by severity of synovial effusion and osteoarthritis in the index stifle.

<p>Kaplan-Meier plots for a population of 85 client-owned dogs. Time to contralateral cranial cruciate ligament rupture was not significantly influenced by severity of synovial effusion (<b>A</b>) or osteophytosis (<b>B</b>) in the index stifle.</p

Severity scoring of stifle radiographs for synovial effusion.

<p>(<b>A–C</b>) Severity of synovial effusion was graded as 0 = normal (A), 1 = mild (B), or 2 = severe (C), using the medial-lateral radiographic view. Severity scoring was based on the magnitude of the soft tissue density within the stifle joint and the dimensions of the intra-patellar fat pad density in the cranial part of the joint. Grading was based on a previously published scale <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106389#pone.0106389-Innes1" target="_blank">[15]</a>.</p

Time to contralateral cranial cruciate ligament rupture stratified by severity of synovial effusion or osteoarthritis in the contralateral stifle.

<p>Kaplan-Meier plots for a population of 85 client-owned dogs. (<b>A</b>) Time to contralateral cranial cruciate ligament rupture was significantly decreased in dogs with Grade 2 radiographic synovial effusion of the contralateral stifle at diagnosis, when compared with the grades of 0 or 1 (<i>p</i><0.001). (<b>B</b>) Time to contralateral cranial cruciate ligament rupture was significantly decreased in dogs with Grade 3 osteophytosis of the contralateral stifle at diagnosis, when compared with the grade 0 and grade 2 (<i>p</i><0.05).</p