Rqc2p
| Ribosome quality control complex subunit 2 | ||
|---|---|---|
| other names |
Translation-associated element 2 |
|
| Mass / length primary structure | 1,038 amino acids , 119,069 Da | |
| Identifier | ||
| External IDs | ||
Rqc2p is a protein found in yeast that is involved in quality control of newly produced proteins on ribosomes .
properties
A newly formed protein on the ribosome that receives the wrong amino acid during translation comes to a standstill and the entire protein synthesis is halted. The two ribosome subunits, 40S and 60S, then separate from one another. The two proteins Ltn1p and Rqc2p bind to the separated 60S subunit of the ribosome and influence the stopped protein synthesis. While Ltn1p binds in the vicinity of the E (exit) site of the ribosome and represents a signal for ubiquitination and thus for proteasomal degradation, Rqc2p plays a rather unusual role. Before the Ltn1p receives the signal for the degradation of the wrongly synthesized protein, further amino acids are first added by Rqc2p. In this case, a protein takes on the role of a template instead of the usual mRNA . The incorporation of these additional amino acids is limited to only two amino acids due to the tRNA used , alanine and threonine . These two amino acids are incorporated in an arbitrary order.
Parallels to heat shock proteins
Similar to heat shock proteins , which act as chaperones to help other proteins fold , Rqc2p regulates the cell cycle in the event of excessive heat, cold or oxidative stress .
Rqc2p signals to the cell that more heat shock proteins are required.
Web links
Individual evidence
- ↑ Claudia Esser, Simon Alberti, Jörg Höhfeld: Cooperation of molecular chaperones with the ubiquitin / proteasome system . In: Biochimica Et Biophysica Acta . tape 1695 , no. 1-3 , November 29, 2004, ISSN 0006-3002 , pp. 171-188 , doi : 10.1016 / j.bbamcr.2004.09.020 , PMID 15571814 .
- ↑ Peter S. Shen, Joseph Park, Yidan Qin, Xueming Li, Krishna Parsawar: Rqc2p and 60S ribosomal subunits mediate mRNA-independent elongation of nascent chains . In: Science . tape 347 , no. 6217 , January 2, 2015, ISSN 0036-8075 , p. 75-78 , doi : 10.1126 / science.1259724 , PMID 25554787 , PMC 4451101 (free full text).
- ↑ Ferruccio Ritossa: Discovery of the heat shock response . In: Cell Stress & Chaperones . tape 1 , no. 2 , June 1, 1996, ISSN 1355-8145 , p. 97-98 , PMID 9222594 , PMC 248460 (free full text).