Immunofluorescence studies of human fibroblasts demonstrate the presence of the complex of elongation factor-1βγd in the endoplasmic reticulum

• DOI: 10.1242/jcs.109.5.1113
• Publication Date: 2021-04-25T16:35:53Z
• Authors: Jo Sanders; Margreet Brandsma; George M. C. Janssen; Jan Dijk; Wim Möller
• Keywords: Cell Nucleus; Cytoplasm; 0303 health sciences; Molecular Sequence Data; Fluorescent Antibody Technique; Fibroblasts; Endoplasmic Reticulum; Peptide Elongation Factors; Peptide Fragments; Cell Line; 03 medical and health sciences; Peptide Elongation Factor 1; Humans; Amino Acid Sequence

ABSTRACT The eukaryotic elongation factor-1 (EF-1) consists of four subunits, EF-1α, EF-1β, EF-1γ and EF-1d which induce efficient transfer of aminoacyltRNA to the ribosome. In this process EF-1α·GTP acts as the carrier of the aminoacyltRNA on its way to the ribosome. After release of aminoacyltRNA to the ribosome under concomitant hydrolysis of GTP, the inactive EF-1α·GDP form is recycled to EF-1α·GTP by EF-1βγd. In eukaryotic cells the concentration of EF-1α exceeds that of the complex βγd by a factor of 5-10. In order to delineate the intracellular localization of the different subunits of EF-1, antibodies against the EF-1 subunits have been elicited and indirect immunofluorescence microscopy experiments were performed. In human fibroblasts, the guanine nucleotide exchange part of EF-1, EF-1βγd, was found to colocalize with the endoplasmic reticulum (ER), displaying a distinct finestructure in its staining pattern. The guanine nucleotidebinding subunit of EF-1, EF-1α, shows a more diffuse distribution throughout the cytoplasm and is, in addition, associated with the nucleus.