Translational regulator RpL10p/Grc5p interacts physically and functionally with Sed1p, a dynamic component of the yeast cell surface.
Biogenesis of an active ribosome complement and a dynamic cell surface complement are two major determinants of cellular growth. In yeast, the 60S ribosomal subunit protein RpL10p/Grc5p functions during successive stages in ribosome biogenesis, specifically rRNA processing, nucle(ol)ar preribosomal subunit assembly, nucleo-cytoplasmic transport and cytoplasmic maturation of ribosomes. Here, we report that a two-hybrid screen identified yeast genes SED1, ACS2 and PLB3 as encoding proteins physically interacting with both ribosomal RpL10p/Grc5p and its human homologue hRpL10p/QMp. SED1 encodes a differentially expressed cell wall protein which is proposed to be first transiently secreted to the plasma membrane as a GPI (glycosylated derivative of phosphoinositol)-anchored form and to be then transferred to the glucan layer of the cell wall. Ectopic expression of SED1 rescues both the aberrant growth phenotype and the translation defect of grc5-1(ts) temperature-sensitive cells. Furthermore, we report that Sed1p associates with translating ribosomes suggesting a novel, cytoplasmic role for Sed1p. ACS2 encodes one of the two yeast acetyl-CoA synthases and represents a key enzyme in one of several metabolic routes to produce acetyl-CoA, which in turn is indispensable for lipid biosynthesis. PLB3 encodes a phospholipase, which is active in the breakdown of membrane lipids. Our results support the view that Grc5p/RpL10p links ribosome function to membrane turnover and cell surface biogenesis.
Oender
Kamil
K
Department of Genetics and General Biology, Paris-Lodron University Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg.
Loeffler
Michael
M
Doppler
Edith
E
Eder
Michaela
M
Lach
Sibylle
S
Heinrich
Felix
F
Karl
Thomas
T
Moesl
Roland
R
Hundsberger
Harald
H
Klade
Torsten
T
Eckl
Peter
P
Dickinson
J Richard
JR
Breitenbach
Michael
M
Koller
Lore
L
D001483:Base Sequence; D002473:Cell Wall / Q000235:genetics / Q000502:physiology; D003066:Coenzyme A Ligases / Q000235:genetics / Q000502:physiology; D005816:Genetic Complementation Test; D008245:Lysophospholipase / Q000235:genetics / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis / Q000235:genetics / Q000502:physiology*; D012269:Ribosomal Proteins / Q000235:genetics / Q000502:physiology*; D012270:Ribosomes / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D017422:Sequence Analysis, DNA; D020798:Two-Hybrid System Techniques; D015003:Yeasts / Q000235:genetics / Q000502:physiology*
D008562:Membrane Glycoproteins; C093333:RPL10 protein, S cerevisiae; D012269:Ribosomal Proteins; C077394:SED1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D008245:Lysophospholipase; C122013:PLB3 protein, S cerevisiae; D003066:Coenzyme A Ligases; C403665:ACSL6 protein, human