Analysis of in vivo consequences of disease-relvant point mutations in p97 (VCP) in Dictostelium discoideum, a simple and powerful model system for functional genomics

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p97 (VCP or valosin-containing protein in mammals and Cdc48p in yeast) is a ubiquitously expressed and evolutionarily highly conserved member of the magnesium-dependent Walker P-loop AAA-ATPases. Mutations in the human p97 gene on chromosome 9p13-p12 cause the autosomal dominant inclusion body myopathy associated with Paget disease of the bone and frontotemporal dementia or IBMPFD. In this project we will study the function of p97 in D. discoideum, a simple and powerful haploid model system for functional genomics as well as an established model for autophagic processes. We have already successfully generated Dictyostelium strains that express endogenous p97 as well as wildtype or mutant R155C p97 fused to GFP or RFP. The latter strain mimics the genetic situation in human IBMPFD patients. Special emphasis of our analyses will be on protein aggregate formation, proteasomal and autophagic dysfunction. We will search for novel p97 binding partners by carrying out immunoprecipitations followed by mass spectrometry. To identify diseaserelevant intracellular signalling pathways, comparative microarray analyses in conjunction with sophisticated bioinformatic methods will be performed. The main goal of this project will be the elucidation of the molecular and cellular consequences of the R155C mutation in Proposal for a DFG-Research Unit: Myofibrillar Myopathies 68 p97 in the Dictyostelium model system and comparison with the human and murine IBMPFD pathology.