Overexpression of translation elongation factor 1A affects the organization and function of the actin cytoskeleton in yeast.
The translation elongation factor 1 complex (eEF1) plays a central role in protein synthesis, delivering aminoacyl-tRNAs to the elongating ribosome. The eEF1A subunit, a classic G-protein, also performs roles aside from protein synthesis. The overexpression of either eEF1A or eEF1B alpha, the catalytic subunit of the guanine nucleotide exchange factor, in Saccharomyces cerevisiae results in effects on cell growth. Here we demonstrate that overexpression of either factor does not affect the levels of the other subunit or the rate or accuracy of protein synthesis. Instead, the major effects in vivo appear to be at the level of cell morphology and budding. eEF1A overexpression results in dosage-dependent reduced budding and altered actin distribution and cellular morphology. In addition, the effects of excess eEF1A in actin mutant strains show synthetic growth defects, establishing a genetic connection between the two proteins. As the ability of eEF1A to bind and bundle actin is conserved in yeast, these results link the established ability of eEF1A to bind and bundle actin in vitro with nontranslational roles for the protein in vivo.
Munshi
R
R
Department of Molecular Genetics and Microbiology, UMDNJ Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Kandl
K A
KA
Carr-Schmid
A
A
Whitacre
J L
JL
Adams
A E
AE
Kinzy
T G
TG
D000199:Actins / Q000378:metabolism*; D002453:Cell Cycle; D002455:Cell Division; D003599:Cytoskeleton / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D005800:Genes, Fungal; D020648:Peptide Elongation Factor 1 / Q000096:biosynthesis* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins
D000199:Actins; D005656:Fungal Proteins; D020648:Peptide Elongation Factor 1; D029701:Saccharomyces cerevisiae Proteins; C410826:TEF1 protein, S cerevisiae