Drosophila translational elongation factor-1gamma is modified in response to DOA kinase activity and is essential for cellular viability.
Drosophila translational elongation factor-1gamma (EF1gamma) interacts in the yeast two-hybrid system with DOA, the LAMMER protein kinase of Drosophila. Analysis of mutant EF1gamma alleles reveals that the locus encodes a structurally conserved protein essential for both organismal and cellular survival. Although no genetic interactions were detected in combinations with mutations in EF1alpha, an EF1gamma allele enhanced mutant phenotypes of Doa alleles. A predicted LAMMER kinase phosphorylation site conserved near the C terminus of all EF1gamma orthologs is a phosphorylation site in vitro for both Drosophila DOA and tobacco PK12 LAMMER kinases. EF1gamma protein derived from Doa mutant flies migrates with altered mobility on SDS gels, consistent with it being an in vivo substrate of DOA kinase. However, the aberrant mobility appears to be due to a secondary protein modification, since the mobility of EF1gamma protein obtained from wild-type Drosophila is unaltered following treatment with several nonspecific phosphatases. Expression of a construct expressing a serine-to-alanine substitution in the LAMMER kinase phosphorylation site into the fly germline rescued null EF1gamma alleles but at reduced efficiency compared to a wild-type construct. Our data suggest that EF1gamma functions in vital cellular processes in addition to translational elongation and is a LAMMER kinase substrate in vivo.
Department of Molecular Genetics, Microbiology and Immunology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Yujie
Y
Fan
Michael
M
Schlierf
Ana Cuervo
AC
Gaspar
Catherine
C
Dreux
Arlette
A
Kpebe
Linda
L
Chaney
Aurelie
A
Mathieu
Christophe
C
Hitte
Olivier
O
Grémy
Emeline
E
Sarot
Mark
M
Horn
Yunlong
Y
Zhao
Terri Goss
TG
Kinzy
Leonard
L
Rabinow
D000818:Animals; D002470:Cell Survival; D017124:Conserved Sequence; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005804:Genes, Lethal / Q000235:genetics; D006801:Humans; D007814:Larva / Q000254:growth & development; D008297:Male; D009068:Movement; D020648:Peptide Elongation Factor 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D019076:Transgenes / Q000235:genetics
D029721:Drosophila Proteins; C095837:Eip93F protein, Drosophila; D020648:Peptide Elongation Factor 1; D012333:RNA, Messenger; D014157:Transcription Factors; D011494:Protein Kinases; C089977:Doa protein, Drosophila; D017346:Protein Serine-Threonine Kinases