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Protein quality control mechanisms and proteinopathies

 

Impact of posttranslational modifications on protein quality control mechanisms and proteinopathies

 

Context

Protein folding is one of the fundamental processes in life, and therefore needs to be tightly regulated. Many cellular quality control systems are in place to ensure that protein homeostasis (proteostasis) is optimally adjusted for a changing environment, facilitating protein folding, translocation and degradation. Among these systems are the molecular chaperones and the major protein degradation systems, namely the ubiquitin proteasome system and autophagy. However, as a result of ageing, mutations or exogenous influences, the capacity of the quality control systems can be exhausted and protein misfolding and aggregation, including amyloid formation, can occur. There are many known diseases in which protein misfolding and aggregation is the underlying cause of the pathological condition; these are referred to as proteinopathies. Proteins can postranslationally be modified after protein biosynthesis. Over the last decade, it has become clear that posttranslational modifications (PTMs) can govern and modulate protein folding, and that aberrant posttranslational modifications can cause or contribute to proteinopathies. 

 

Research objectives

Olzscha et al. have demonstrated that essential hub proteins are sequestered inside amyloid-like aggregates, that acetylation can influence crucial regulator proteins in proteasomal degradation and autophagy and that hyperacetylation of proteins leads to amyloid formation in neural cells and can be partially reversed by treatment with CBP/p300-specific bromodomain inhibitors. Combining biochemical, cell biological and proteomic approaches, we are working towards a better understanding of how posttranslational modifications can alter proteostasis and cause or accompany proteinopathies, and together with academic and industrial partners, how we might translate this into therapeutic benefit. Dissecting which regulatory mechanisms in protein quality control systems and proteinopathies may be affected by alterations of major PTMs including acetylation, ubiquitination, glycosylation and citrullination, current challenges and projects include: 

How will a different pattern of PTMs, particularly acetylation and ubiquitination affect protein folding and stability? Is aberrant acetylation detectable and does it lead to protein misfolding? If so, would this be a direct effect or via a decreased UPS-mediated degradation? Are molecular chaperones involved? Are proteins differently recognised by molecular chaperones upon different modification? Do different structural regions in proteins with defined/undefined structures (e.g. IURs) have a different propensity to misfold upon applying PTMs? How is the process of protein shuttling within the UPS affected, if different lysine residues are acetylated? If it is affected, which factors are involved? Are there implications in ageing-related diseases, where the underlying proteins are misfolded, such as Alzheimer’s, Parkinson’s and Huntington’s Disease? And how can this be reverted and translated into therapeutic benefit? 

 

Available research positions

Enquiries for research positions are welcome. If you are motivated to solve one or more of the above-mentioned questions, please send your application via email to: Email

 

Applications should include a letter of motivation; curriculum vitae; certificates; publications if available; addresses including emails of two academic referees. 

 

Direktor:
Prof. Dr. Guido Posern

AG Proteinopathies: 
Dr. Heidi Olzscha
Tel.: +49 (0)345 557 3847
Fax: +49 (0)345 557-3811
Email Heidi Olzscha

Hausanschrift:
Institut für Physiologische Chemie
Hollystrasse 1
06114 Halle (Saale)

Assistenz der Institutsleitung:
Ines Knipping
Telefon: (0345) 557-3812 
Fax:        (0345) 557-3811
Email:    Email