Control of Alzheimer's Amyloid Beta Toxicity by the High Molecular Weight Immunophilin FKBP52 and Copper Homeostasis in Drosophila

FK506 binding proteins (FKBPs), also called immunophilins, are prolyl-isomerases (PPIases) that participate in a wide variety of cellular functions including hormone signaling and protein folding. Recent studies indicate that proteins that contain PPIase activity can also alter the processing of Alzheimer's Amyloid Precursor Protein (APP). Originally identified in hematopoietic cells, FKBP52 is much more abundantly expressed in neurons, including the hippocampus, frontal cortex, and basal ganglia. Given the fact that the high molecular weight immunophilin FKBP52 is highly expressed in CNS regions susceptible to Alzheimer's, we investigated its role in Aβ toxicity. Towards this goal, we generated Aβ transgenic Drosophila that harbor gain of function or loss of function mutations of FKBP52. FKBP52 overexpression reduced the toxicity of Aβ and increased lifespan in Aβ flies, whereas loss of function of FKBP52 exacerbated these Aβ phenotypes. Interestingly, the Aβ pathology was enhanced by mutations in the copper transporters Atox1, which interacts with FKBP52, and Ctr1A and was suppressed in FKBP52 mutant flies raised on a copper chelator diet. Using mammalian cultures, we show that FKBP52 (−/−) cells have increased intracellular copper and higher levels of Aβ. This effect is reversed by reconstitution of FKBP52. Finally, we also found that FKBP52 formed stable complexes with APP through its FK506 interacting domain. Taken together, these studies identify a novel role for FKBP52 in modulating toxicity of Aβ peptides

Phalangerid periotics

14 p. : ill. ; 26 cm.Includes bibliographical references (p. 14).The morphology of the periotic in the extant trichosurin possums Strigocuscus celebensis and Wyulda squamicaudata is described and compared with that of various species of extant and extinct phalangerid marsupials. The periotic morphologies of S. celebensis and W. squamicaudata show a number of similarities with those of brushtailed possums of the genus Trichosurus, strengthening the case for a monophyletic tribe Trichosurini consisting of these three genera. Comparisons with periotics of possums from the Tertiary Riversleigh deposits of Queensland that were previously assigned on the basis of craniodental anatomy to Trichosurus and Strigocuscus suggest that, despite some similarities, the three extant trichosurins may be more closely related to each other than to the Riversleigh taxa. A revised morphological diagnosis of the Trichosurini is provided, incorporating these data

Eosinophil Major Basic Protein-1 Does Not Contribute to Allergen-Induced Airway Pathologies in Mouse Models of Asthma

The relationship between eosinophils and the development of Ag-induced pulmonary pathologies, including airway hyper-responsiveness, was investigated using mice deficient for the secondary granule component, major basic protein-1 (mMBP-1). The loss of mMBP-1 had no effect on OVA-induced airway histopathologies or inflammatory cell recruitment. Lung function measurements of knockout mice demonstrated a generalized hyporeactivity to methacholine-induced airflow changes (relative to wild type); however, this baseline phenotype was observable only with methacholine; no relative airflow changes were observed in response to another nonspecific stimulus (serotonin). Moreover, OVA sensitization/aerosol challenge of wild-type and mMBP-1(-/-) mice resulted in identical dose-response changes to either methacholine or serotonin. Thus, the airway hyper-responsiveness in murine models of asthma occurs in the absence of mMBP-1