p23rab2, a ras-like GTPase with a -GGGCC C-terminus, is isoprenylated but not detectably carboxymethylated in NIH3T3 cells.
With the development of a specific anti-rab2 antiserum, p23rab2, a ras-like GTPase with a -GGGCC C-terminus, has been localized mainly to the particulate (P100) fraction in NIH3T3 cells, although a small amount of this protein also appears in the soluble fraction. The endogenous p23rab2 is isoprenylated in intact cells, and recombinant murine p23rab2 is also isoprenylated in an in vitro system using reticulocyte lysate. Both the cytosolic and membrane-bound forms of p23rab2 are isoprenylated in intact cells. Recombinant p23rab2 is specifically geranylgeranylated at one or both of the C-terminal cysteine residues in the in vitro system. Blocking isoprenoid synthesis with lovastatin results in an accumulation of a totally cytosolic unisoprenylated form, indicating that isoprenylation is a prerequisite for membrane association of p23rab2. Surprisingly, unlike p21ras and p25rab3A, no carboxymethylation of p23rab2 is detectable in either the soluble or particulate fractions.
Wei
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Department of Biochemistry, University of Rochester, New York 14642.
Lutz
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R
Sinensky
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Macara
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D016475:3T3 Cells; D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002451:Cell Compartmentation; D002462:Cell Membrane / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D051228:Geranyltranstransferase; D008745:Methylation; D051379:Mice; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D014166:Transferases / Q000378:metabolism; D020693:rab2 GTP-Binding Protein
D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D051228:Geranyltranstransferase; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020693:rab2 GTP-Binding Protein; D003545:Cysteine