Hypotheses and aims of thesis Sample Clauses

Hypotheses and aims of thesis. Although there is evidence that VAPB functions in the UPR, the data is inconsistent and the role of VAPB P56S in the UPR is unclear. Additionally, the mechanisms behind TDP-43 mislocalisation and cytoplasmic accumulation in VAPB P56S transgenic mice are not properly known. Finally, disturbances to ER-mitochondria associations have been reported in several neurodegenerative diseases including ALS/FTD. Our research group has identified VAPB and PTPIP51 as binding partners that act to tether ER with mitochondria and this provides a molecular target for potential therapy. Therefore the hypotheses that form the basis of this thesis are: 1. That VAPB functions in the UPR and that VAPB P56S is defective in this function. This was tested by monitoring the UPR in cells in which expression of VAPB and VAPB P56S was experimentally manipulated. 2. That ER stress, VAPB and VAPB P56S affect TDP-43 processing and distribution. This was tested by monitoring TDP-43 processing and subcellular distribution in cells following ER stress and following experimental manipulation of VAPB and VAPB P56S expression. In addition the effect of phosphorylation of amino acids within the TDP-43 nuclear localisation signal on nuclear/cytoplasmic distribution was investigated. 3. That the interaction of VAPB with PTPIP51 and their regulation of ER- mitochondria associations represent a new therapeutic target for neurodegenerative diseases. To test this hypothesis, a screen was developed that should facilitate the identification of small molecules which modulate the VAPB-PTPIP51 interaction. It is hoped that investigating these hypotheses will provide a deeper understanding of mechanisms underlying the pathology of ALS type 8 and enable research into novel therapeutic targets. VAPB Endoplasmic reticulum transmembrane protein • PTPIP51: ER-mitochondria interaction (Xx Xxx et al., 2012; Xxxxxx et al., 2014) • Nir2, OSBP, CERT: lipid metabolism (Xxxxxx et al., 2003; Amarilio et al., 2005; Xxxxxx et al., 2006) • ATF6: UPR inhibition (Xxxxxxx et al., 2008) PTPIP51 Outer mitochondrial membrane protein VAPB: ER-mitochondria interaction (Xx Xxx et al., 2012; Xxxxxx et al., 2014) TDP-43 90% nuclear, 10% cytoplasmic • hnRNP A2/B1 • hnRNP A1 • hnRNP C1/C2 • hnRNP B3: RNA metabolism including splicing and transcription, mRNA transport and degradation, protein synthesis from mRNA (Xxxxxxx et al., 2005; X'Xxxxxxxx et al., 2009; Xxxxxxxx et al., 2009; Xxxx et al., 2010; Xxxxxxx and Baralle, 2012)