Related Experiment Video
Updated: Aug 19, 2026

In vivo Interrogation of Central Nervous System Translatome by Polyribosome Fractionation
Published on: April 30, 2014
Stop-transfer activity of hydrophobic sequences depends on the translation system
M Spiess1, C Handschin, K P Baker
1Department of Biochemistry, University of Basel, Switzerland.
Abstract:
Signal and stop-transfer sequences are the known determinants involved in topogenesis of integral membrane proteins. To study the characteristics of stop-transfer sequences, artificial proteins have been created on the DNA level based on the cDNA of the asialoglycoprotein receptor H1. Its internal signal/anchor domain initiates translocation of the downstream sequence across the endoplasmic reticulum membrane. The ability of several hydrophobic sequences inserted into the translocating polypeptide to stop further transfer was analyzed by translation of the fusion proteins using the wheat germ extract and rabbit reticulocyte lysate systems with dog pancreas microsomes. We discovered that some of the sequences behave differently with respect to translocation across the membrane depending on the translation system. Expression of one of the fusion proteins in fibroblasts showed that the reticulocyte lysate system reflects more closely the in vivo situation than the wheat germ system. Our results suggest that in a homologous system the translating ribosomes interact with the translocation machinery and influence the termination of polypeptide transfer by hydrophobic sequences.
Related Concept Videos
Termination of Translation
Leaky Scanning
Insertion of Single-pass Transmembrane Proteins in the RER
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Post-translational Translocation of Proteins to the RER
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Termination of Translation
Translational Regulation

