The Sec61 complex is the central component of the protein translocation apparatus of the ER membrane. We have addressed the role of the b subunit (Sec61 b ) during cotranslational protein translocation. With a reconstituted system, we show that a Sec61 complex lacking Sec61 b is essentially inactive when elongation and membrane targeting of a nascent chain occur at the same time. The translocat...

The Sec61 complex is the central component of the protein translocation apparatus of the ER membrane. We have addressed the role of the beta subunit (Sec61beta) during cotranslational protein translocation. With a reconstituted system, we show that a Sec61 complex lacking Sec61beta is essentially inactive when elongation and membrane targeting of a nascent chain occur at the same time. The tran...

Dipeptidyl peptidase IV (DPPIV) is a membrane glycoprotein with a type II orientation in the plasma membrane. As shown in a cell-free translation system, the amino-terminal 34 amino acids of rat DPPIV are involved in translocating nascent polypeptide across the membrane of microsomes and in anchoring the translocated polypeptide in the microsomal membrane. The amino-terminal sequence performing...

The evolutionarily conserved fungal arginine attenuator peptide (AAP), as a nascent peptide, stalls the translating ribosome in response to the presence of a high concentration of the amino acid arginine. Here we examine whether the AAP maintains regulatory function in fungal, plant, and animal cell-free translation systems when placed as a domain near the N terminus or internally within a larg...

Southern rice black-streaked dwarf virus (SRBSDV) is transmitted efficiently only by white-backed planthopper (WBPH, Sogatella furcifera) in a persistent propagative manner. Here we used a yeast two-hybrid system to investigate the interactions between the SRBSDV- P10 and the cDNA library of WBPH. Of 130 proteins identified as putative interactors, 28 were further tested in a retransformation a...

In living systems, polypeptide chains are synthesised on ribosomes, molecular machines composed of over 50 protein and nucleic acid molecules. As nascent chains emerge from the ribosomal exit tunnel and into the cellular environment, the majority must fold into specific structures in order to function. In this article we discuss recent approaches designed to reveal how such folding occurs and r...