Disrupting the geranylgeranylation at the C-termini of the shrimp Ras by depriving guanine nucleotide binding at the N-terminal.
In order to assess the effects of guanine nucleotide binding on the geranylgeranylation at the CAAX box of the shrimp Ras, we experimented with the shrimp Penaeus japonicus Ras (S-Ras) which is geranylgeranylated at the C-termini, shares 85% homology with mammalian K(B)-Ras protein and demonstrates identity in the guanine nucleotide binding domains (Huang C-F, Chuang N-N. 1999. J Exp Zool 283:510-521). Several point mutations in the S-ras gene were generated at codons 12 (G12V), 61 (Q61K), and 116 (N116I). The bacterially expressed mutant S-Ras proteins, G12V and Q61K, were bound with GTP without hydrolysis. In contrast, the mutant S-Ras N116I was defective in its ability to bind any guanine nucleotides. Autoradiography studies showed that the purified shrimp protein geranylgeranyltransferase I (Lin R-S, Chuang N-N. 1998. J Exp Zool 281:565-573) was unable to catalyze the transfer of [(3)H]-geranylgeranylpyrophosphate to this mutant N116I but very competently caused the geranylgeranylation of GTP-locked mutants, G12V and Q61K. These results demonstrate that the geranylgeranylation at the CAAX box of the shrimp Ras protein requires the proper binding of guanine nucleotide at its N-terminal region. J. Exp. Zool. 286:441-449, 2000.
Huang
C F
CF
Department of Zoology, National Taiwan University and Institute of Zoology, Academia Sinica, Nankang, Taipei, Taiwan.
Chuang
N N
NN
D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D000818:Animals; D033364:Decapoda; D006150:Guanine Nucleotides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D016297:Mutagenesis, Site-Directed; D017368:Protein Prenylation; D015183:Restriction Mapping; D013329:Structure-Activity Relationship; D018631:ras Proteins / Q000378:metabolism*
D006150:Guanine Nucleotides; D019883:Alkyl and Aryl Transferases; C083291:geranylgeranyltransferase type-I; D018631:ras Proteins