LMPD Database

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LMP011162

UniProt Annotations

Entry Information
Gene Nameprotein-S-isoprenylcysteine O-methyltransferase A
Protein EntryICMTA_ARATH
UniProt IDQ9FMW9
SpeciesArabidopsis
Comments
Comment typeDescription
Biophysicochemical PropertiesKinetic parameters: KM=22.7 uM for AFC as methyl acceptor {ECO:0000269|PubMed:12472689}; KM=13.7 uM for AGGC as methyl acceptor {ECO:0000269|PubMed:12472689}; Vmax=5.0 pmol/min/mg enzyme toward AFC as methyl acceptor {ECO:0000269|PubMed:12472689}; Vmax=3.7 pmol/min/mg enzyme toward AGGC as methyl acceptor {ECO:0000269|PubMed:12472689};
Catalytic ActivityS-adenosyl-L-methionine + protein C-terminal S-farnesyl-L-cysteine = S-adenosyl-L-homocysteine + protein C- terminal S-farnesyl-L-cysteine methyl ester.
CofactorName=Zn(2+); Xref=ChEBI:CHEBI:29105; Evidence={ECO:0000250}; Note=Divalent metal cations. Probably Zn(2+). {ECO:0000250};
Disruption PhenotypeNo visible phenotype; due to redundancy with ICMTB. Icmta and icmtb double mutants have altered phyllotaxis, fasciated stems and development of axillary flowers. {ECO:0000269|PubMed:18641086}.
Enzyme RegulationInhibited by farnesylthioacetic acid (FTAA) and N-acetyl-S-trans, trans-farnesyl-l-cysteine (AFC).
FunctionCatalyzes the post-translational methylation of isoprenylated C-terminal cysteine residues, resulting in the modulation of the function of prenylated proteins. Involved in negative regulation of abscisic acid signaling. Carboxyl methylation is a reversible and potentially regulated step in the post-translational modification of prenylated proteins. {ECO:0000269|PubMed:11135111, ECO:0000269|PubMed:11352465, ECO:0000269|PubMed:12472689, ECO:0000269|PubMed:18957507}.
InductionNot induced by abscisic acid or auxin. {ECO:0000269|PubMed:18957507}.
MiscellaneousICMTA is less widely expressed and has a lower catalytic activity than ICMTB.
Sequence CautionSequence=ABK28709.1; Type=Erroneous termination; Positions=198; Note=Translated as stop.; Evidence={ECO:0000305};
SimilarityBelongs to the class VI-like SAM-binding methyltransferase superfamily. Isoprenylcysteine carboxyl methyltransferase family. {ECO:0000305}.
Subcellular LocationEndoplasmic reticulum membrane {ECO:0000269|PubMed:11135111, ECO:0000269|PubMed:18641086}; Multi- pass membrane protein {ECO:0000269|PubMed:11135111, ECO:0000269|PubMed:18641086}.
Tissue SpecificityExpressed primarily in flowers, stems, leaves and roots. Almost not expressed in siliques. Detected in root tips and vascular tissues of roots, cotyledons, petiols, hypocotyls, filaments, pollen grains and the distal and proximal portions of the gynoecium. {ECO:0000269|PubMed:11352465, ECO:0000269|PubMed:12472689}.