engleski

Modelling the schizophrenia-related aggregation of NPAS3 and CRMP1 in neuroblastoma cells

Chronic mental illness affects millions of people every year, while its origins and mechanisms remain unclear. Since symptoms of neurodegenerative and mental disorders are similar, our research focuses on protein aggregation. Protein aggregation changes the structure of protein and can cause loss of function or gain of a novel toxic function. There are several proteins characterized as aggregating in mental illnesses, of which we focused on Collapsin Response Mediator Protein 1 (CRMP1) and Neuronal PAS Domain Protein 3 (NPAS3). We expressed variants of mentioned proteins in neuroblastoma cell line and assessed them by immunofluorescence. CRMP1 has been detected as insoluble in brains of mental disorder patients and seen to aggregate in cell culture. In our research we wanted to confirm aggregation of the long and short CRMP1 variants. The long variant is seen to aggregate alone, while short variant is only known to co-aggregate with other proteins. Since the long variant od CRMP1 has a longer N-terminal section unlike the short variant, we investigated its truncation too. However, we did not see aggregation of long and short CRMP1 variants when expressed alone, nor the effect of N-terminal truncations. Thus, we believe CRMP1 has greater tendency to co-aggregate with other proteins and the following research should explore it in more detail. Meanwhile, genetic studies have implicated a mutated version of NPAS3 in mental disorders. Also, mutant NPAS3 has been seen as insoluble in cell culture. We examined aggregation of full- length wild type and mutated NPAS3 variants, along with the major NPAS3 structural regions. We observed that mutated NPAS3 does not enter the nucleus and therefore cannot perform its normal function as transcription factor. Interestingly, we have seen that the bHLH1 region of NPAS3 can aggregate by itself and is stabilised by presence of the PAS region. Our results confirmed that NPAS3 aggregation is a consequence of mutation, but there could be other mechanisms which include disruption of bHLH1 region. Next steps should include further investigation of bHLH1 and PAS regions of NPAS3, with regards to mutation and translocation. Finally, this and similar research could result in model of aggregation for both proteins, which could be translated to other proteins implicated in mental illness.

protein aggregation ; NPAS3 ; CRMP1 ; mental illness ; mental disorders

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