Adult human liver contains intermediate-type proteasomes with different enzymatic properties
Journal Title: Annals of Hepatology - Year 2014, Vol 13, Issue 4
Abstract
Background. The 20S proteasome is the proteolytic core of the major intracellular protein degradative system, the ubiquitin-proteasome system. Since little is known about proteasomes of human liver, we have investigated the proteasome spectrum in adult human liver. Material and methods. 20S proteasomes were chromatographically purified from adult human liver and from HuH7 cells. They were divided into subpopulations and subtypes and characterized with regard to their proteolytic activities using short fluorogenic oligo- and long poly-peptide substrates. Their subunit composition was studied by immunoblotting. Results. Proteasomes from adult human liver tissue can be separated into three subpopulations (I, II, III), each of which is composed of several subtypes, which total to a spectrum of 14 different subtypes. Two minor subtypes contain only the immuno-subunits β1i and β5i but not their standard counterparts; all others are intermediate subtypes containing β1 and β5 standard- and β1i and β5i immuno-subunits in various compositions. With regard to the proteolytic activities we observed that a decreasing content of subunit β1i in the subtypes goes along with a decreasing ratio of chymotrypsin-like/caspase-like activity, whereas the degradation rate of a 30 mer polypeptide substrate increased with decreasing β1i content. By comparison, 20S proteasomes from HuH7 cells do not contain immuno-subunits but are pure standard proteasomes, which can be separated into three subtypes. Conclusion. These findings suggest that adult human liver contains a spectrum of 14 different 20S proteasome subtypes with different enzymatic properties reflecting most probably an adaptive response of liver cell functions to challenging factors during lifetime.
Authors and Affiliations
Sabrina Gohlke, Alexander Kloß, Michael Tsokos, Kathrin Textoris-Taube, Christin Keller, Peter-Michael Kloetzel, Burkhardt Dahlmann
Keywords
Related Articles
- EP ID EP78421
- DOI -
- Views 153
- Downloads 0
Could TIPS be Applied in All Kinds of Portal Vein Thrombosis: We are not Sure!
-
Hepatitis C Virus Infection Outcomes Among Immigrants to Canada: A Retrospective Cohort Analysis
Introduction and aim. HCV-infected immigrants contribute to the total prevalence in Canada and other developed nations. Little is known about engagement in care, access to service, and treatment outcomes in recipients of...
Early Successes in an Open Access, Provincially Funded Hepatitis C Treatment Program in Prince Edward Island
Introduction. The availability of curative hepatitis C therapies has created an opportunity to improve delivery and access. Local providers, government, industry, and community groups in Prince Edward Island developed an...
Gene expression profiling reveals key genes and pathways related to the development of non-alcoholic fatty liver disease
Background. This study aims to identify key genes and pathways involved in non-alcoholic fatty liver disease (NAFLD). Materialand methods. The dataset GSE48452 was downloaded from Gene Expression Omnibus, including 14 c...
Celebrating fifteen years of Annals of Hepatology publication: The international, open access, clinical journal devoted to liver diseases