Calcium stimulation of polyphenylalanine synthesis in a bovine heart cell-free system

Ruiz, N.; Krauskopf, Manuel

doi:10.1016/0024-3205(80)90505-6

Cited by 6 publications

(1 citation statement)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The process of translation is carried out by ribosomes and their associated factors. In eukaryotic cells, protein translation takes place at the 80S ribosome, which consists of a small 40S subunit [containing 18S rRNA and ∼33 different proteins] and a large 60S subunit [containing 5S rRNA, 5,8 rRNA, 28S rRNA, and ∼49 different proteins]. − Translation is initiated at the start codon of mRNA by the assembly of the 40S ribosomal subunit with an initiator tRNA and the 60S subunit to form a translationally active 80S ribosome. − After initiation, repetitive codon-directed addition of aminoacyl-tRNAs leads to elongation of the polypeptide chain until the final mRNA stop codon is reached and the polypeptide dissociates from the ribosome. − In recent years, several studies have provided strong evidence that Ca 2+ plays a crucial role in the regulation of eukaryotic protein translation. − Kumar et al, found that calmodulin antagonists block the initiation of protein synthesis, indicating that CaM or a very similar Ca 2+ -binding protein might be involved in the process. CaM is a ubiquitously expressed Ca 2+ -binding protein that is involved in a large number of regulatory processes and is highly conserved throughout eukaryotic organisms. − Calmodulin is a major transmitter of Ca 2+ signals in cells and interacts with a multitude of different proteins in response to intracellular [Ca 2+ ] changes and thereby participates in various signaling pathways that regulate processes such as cell proliferation, learning and memory, growth, and movement. − A number of free 40S and 60S ribosomal proteins and other proteins associated with ribosomes have been found to interact with CaM. − These findings support the idea that CaM may play a role in protein synthesis .…”

mentioning

confidence: 99%

Calcium-Dependent Interaction of Calmodulin with Human 80S Ribosomes and Polyribosomes

et al. 2012

View full text Add to dashboard Cite

Ribosomes are the protein factories of every living cell. The process of protein translation is highly complex and tightly regulated by a large number of diverse RNAs and proteins. Earlier studies indicate that Ca(2+) plays a role in protein translation. Calmodulin (CaM), a ubiquitous Ca(2+)-binding protein, regulates a large number of proteins participating in many signaling pathways. Several 40S and 60S ribosomal proteins have been identified to interact with CaM, and here, we report that CaM binds with high affinity to 80S ribosomes and polyribosomes in a Ca(2+)-dependent manner. No binding is observed in buffer with 6 mM Mg(2+) and 1 mM EGTA that chelates Ca(2+), suggesting high specificity of the CaM-ribosome interaction dependent on the Ca(2+) induced conformational change of CaM. The interactions between CaM and ribosomes are inhibited by synthetic peptides comprising putative CaM-binding sites in ribosomal proteins S2 and L14. Using a cell-free in vitro translation system, we further found that these synthetic peptides are potent inhibitors of protein synthesis. Our results identify an involvement of CaM in the translational activity of ribosomes.

show abstract