title: Association of calcineurin with the COPI protein Sec28 and the COPII protein Sec13 revealed by quantitative proteomics.
abstract: Calcineurin is a calcium-calmodulin-dependent serine/threonine specific protein phosphatase operating in key cellular processes governing responses to extracellular cues. Calcineurin is essential for growth at high temperature and virulence of the human fungal pathogen Cryptococcus neoformans but the underlying mechanism is unknown. We performed a mass spectrometry analysis to identify proteins that associate with the calcineurin A catalytic subunit (Cna1) in C. neoformans cells grown under non-stress and high temperature stress conditions. A novel prioritization strategy for mass spectrometry data from immunoprecipitation experiments identified putative substrates and proteins potentially operating with calcineurin in common pathways. Cna1 co-purified with proteins involved in membrane trafficking including the COPI component Sec28 and the COPII component Sec13. The association of Cna1 with Sec28 and Sec13 was confirmed by co-immunoprecipitation. Cna1 exhibited a dramatic change in subcellular localization during high temperature stress from diffuse cytoplasmic to ER-associated puncta and the mother-bud neck and co-localized with Sec28 and Sec13.
authors: Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America. Lukasz.kozubowski@duke.edu
authors: Lukasz
authors: L
authors: Kozubowski
authors: J Will
authors: JW
authors: Thompson
authors: Maria E
authors: ME
authors: Cardenas
authors: M Arthur
authors: MA
authors: Moseley
authors: Joseph
authors: J
authors: Heitman
mesh_terms: D019703:Calcineurin / Q000378:metabolism*; D020755:Coat Protein Complex I / Q000378:metabolism*; D003455:Cryptococcus neoformans / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D008954:Models, Biological; D011485:Protein Binding; D021381:Protein Transport; D040901:Proteomics / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013312:Stress, Physiological; D013696:Temperature
chemical_list: D020755:Coat Protein Complex I; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D019703:Calcineurin