Stalled nascent polypeptides in health and disease

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  • Writer 최고관리자
  • 2017-11-01


[BK21 Plus Seminar]

▶Subject: Stalled nascent polypeptides in health and disease

▶Speaker: Young-Jun Choe, Ph.D. (Max Planck Institute of Biochemistry)
▶Date: 4:00PM/Nov, 2(Thur.)/2017
▶Place: Life Science Bldg. #104
Translation of messenger RNAs lacking a stop codon (non-stop mRNAs) results in the addition of a carboxy-terminal poly-lysine tract to the nascent polypeptide due to the translation of polyA region in mRNAs. Charge interaction between poly-lysine and phosphates in the exit channel of ribosomes causes translational stalling. Non-stop proteins and other stalled nascent chains are recognized by the ribosome quality control (RQC) machinery and targeted for proteasomal degradation. Failure of this process leads to neurodegeneration by unknown mechanisms. I discovered that deletion of the E3 ubiquitin ligase Ltn1p in yeast, a key RQC component, causes stalled proteins to form detergent-resistant aggregates. Aggregation is dependent on a C-terminal alanine/threonine tail that is added to stalled polypeptides by the RQC component, Rqc2p. The aggregates sequester multiple cytosolic chaperones and thereby interfere with general protein quality control pathways. These findings can explain the proteotoxicity of ribosome-stalled polypeptides and demonstrate the essential role of the RQC in maintaining protein homeostasis. In the seminar, I will also discuss the recent approach to identify endogenous stalled polypeptides in cells.

▶Inquiry: Prof. Yoontae Lee, Cheol-Sang Hwang (279-2352)

* This seminar will be given in English.
Please refrain from taking photos during seminars. *