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Protein degradation pathways

Our research interest lies in understanding how pathogenic proteins can be eliminated from the cells and their components recycled. In particular our research focuses on oncogenic protein degradation in relation to biology of cancer.

There are two major fundamentally different mechanisms by which cells degrade proteins for turnover and recycling purposes: the lysosome and the proteasome. Our research uses a creative combination of pharmacological, biochemical and genetic approaches to rigorously investigate the biological significance of these degradation mechanisms in normal and cancer cells.

Hence, our aim is to understand the complexity of various degradation systems and its explicit interactions and mechanisms, that might provide a foundation for the development of diagnostic strategies and major conceptual advance to uncover novel therapeutic drug targets in malignancies as well as in other human disorders.

Current research projects

Ubiquitin-Proteasome System (UPS) in Cancer

The Ubiquitin-Proteasome System (UPS) involves the targeting of polyubiquitination proteins for recognition and processing by the 26S proteasome, a multicatalytic enzyme complex that degrades the proteins, and recycles ubiquitin. The ubiquitylation process is carried out by three classes of enzymes; E1 (activating enzyme), E2 (conjugating enzyme) and E3 (ubiquitin ligase), as well as DUB (deubiquitinating enzymes).

Many proteasome target proteins include a broad array of regulatory proteins that play important roles in cell cycle progression, cell development and differentiation, DNA damage responses, and tumorgenesis. In addition, aberrations in the components of the ubiquitin proteasome pathway are commonly observed in many cancers. We are interested in understanding the role of UPS in cancer and to investigate the possibility of targeting different steps the ubiquitin-proteasome system for cancer treatment.

Autophagy Pathways in Cancer

Proteins destined for lysosomal degradation can reach the lysosome by a variety of means and autophagy is one regulated pathway of lysosomal degradation in mammalian cells. There are three main processes of autophagy; of which we are focusing on is macroautophagy and chaperone-mediated autophagy CMA.

Autophagy in Cancer:

Activation of autophagy, as one regulated pathway of lysosomal degradation, confers stress resistance and sustains cancer cell survival under adverse conditions. Moreover, activation of autophagy has been implicated in mediating resistance to existing anticancer therapy. However, the role of autophagy in cancer is complex and our aim is to investigate the impact of manipulating autophagy pathways to understand the contribution of factors and signaling that might regulate tumorigenesis and chemoresistance.

Chaperone-mediated Autophagy (CMA) in Cancer:

In a mammalian cell, chaperone-mediated autophagy (CMA) is one of the types of autophagy that is specific to breakdown of protein. Beyond its selectivity for proteins, another unique feature of this type of autophagy is that proteins are directly transported into the lysosome for degradation during CMA. Depending on which proteins are degraded by this pathway, CMA can perform various physiological and pathological functions. To date the role of CMA in cancer cells has remained obscure and the physiological importance of CMA in cancer is currently not defined. Therefore, our research intends to investigate the CMA pathway in depths both at cellular and organismal level, in order to explore the intriguing possible role of CMA in various human cancers.

Group members

Yuqing HaoPostdoc
Merve KacalDoktorand
Helin NorbergForskargruppsledare, Senior forskare

Alumni

Tao Cui
Mathilda Eriksson
Kristin Uth
Adi Zheng

Selected publications

29803676

29569651

28993478

28819410

28614715

26577179

26323688

25801023

25654545

23913924

23246432

21962518

Contact us

Senior forskare

Helin Norberg

Enhet: Norberg Helin grupp - Signalvägar för proteinnedbrytning
E-post: helin.norberg@ki.se