John W. B. Hershey

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Protein synthesis in all cells begins with the ordered binding of the small ribosomal subunit to messenger RNA (mRNA) and transfer RNA (tRNA). In eukaryotes, translation initiation factor 3 (eIF3) is thought to play an essential role in this process by influencing mRNA and tRNA binding through indirect interactions on the backside of the 40S subunit. Here(More)
The eukaryotic initiation factor 3 (eIF3) plays an important role in translation initiation, acting as a docking site for several eIFs that assemble on the 40S ribosomal subunit. Here, we use mass spectrometry to probe the subunit interactions within the human eIF3 complex. Our results show that the 13-subunit complex can be maintained intact in the gas(More)
Eukaryotic initiation factor 3 (eIF3) is a 12-subunit protein complex that plays a central role in binding of initiator methionyl-tRNA and mRNA to the 40 S ribosomal subunit to form the 40 S initiation complex. The molecular mechanisms by which eIF3 exerts these functions are poorly understood. To learn more about the structure and function of eIF3 we have(More)
Incubating cells at elevated temperatures causes an inhibition of protein synthesis. Mild heat stress at 41-42 degrees C inhibits the fraction of active, polysomal ribosomes from greater than 60% (preheating) to less than 30%. A return to 37 degrees C leads to an increase in protein synthesis, termed "recovery." Continuous incubation at 41-42 degrees C also(More)
Protein synthesis in mammalian cells requires initiation factor eIF3, an approximately 800-kDa protein complex that plays a central role in binding of initiator methionyl-tRNA and mRNA to the 40 S ribosomal subunit to form the 48 S initiation complex. The eIF3 complex also prevents premature association of the 40 and 60 S ribosomal subunits and interacts(More)
The association of mRNA and ribosomes with the cytoskeleton of eucaryotic cells may be important for protein synthesis and its regulation. HeLa cells were gently lysed with detergent, and soluble and cytoskeletal framework subfractions were prepared by centrifugation. We analyzed these fractions for ribosomes and confirmed earlier findings that polysomes(More)
The assembly of ribosomes in bacterial cells is a complex process that remains poorly characterized. The in vitro assembly of active ribosomal subunits from purified RNA and protein components indicates that all of the information for proper assembly resides in the primary sequences of these macromolecules. On the other hand, the in vitro requirement of(More)
The delivery of Met-tRNA(i) to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNA(i). We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in yeast and plants. A human MFC free of the ribosome also is(More)
A human liver cDNA encoding the beta subunit of protein synthesis initiation factor 2 (eIF-2) was isolated and sequenced. The 1416 bp cDNA encodes a protein of 333 amino acids (38,404 daltons) with characteristics that resemble authentic purified eIF-2 beta. De novo synthesized eIF-2 beta from cDNA transcripts incorporates into endogenous rabbit eIF-2(More)