Q93W54 · ICMTB_ARATH
- ProteinProtein-S-isoprenylcysteine O-methyltransferase B
- GeneICMTB
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids197 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Catalyzes 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.
Miscellaneous
ICMTB is more widely expressed and has a higher catalytic activity than ICMTA.
Catalytic activity
- [protein]-C-terminal S-[(2E,6E)-farnesyl]-L-cysteine + S-adenosyl-L-methionine = [protein]-C-terminal S-[(2E,6E)-farnesyl]-L-cysteine methyl ester + S-adenosyl-L-homocysteine
Cofactor
Note: Divalent metal cations. Probably Zn2+.
Activity regulation
Inhibited by farnesylthioacetic acid (FTAA) and N-acetyl-S-trans, trans-farnesyl-l-cysteine (AFC).
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
5 μM | AFC as methyl acceptor | |||||
3 μM | AGGC as methyl acceptor |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
220 pmol/min/mg | toward AFC as methyl acceptor | ||||
296 pmol/min/mg | toward AGGC as methyl acceptor |
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 116-119 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: HKLV | ||||||
Binding site | 124 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: Y | ||||||
Binding site | 129-132 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: HPSY | ||||||
Binding site | 166 | substrate | ||||
Sequence: R | ||||||
Binding site | 170 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | endoplasmic reticulum | |
Cellular Component | endoplasmic reticulum membrane | |
Molecular Function | protein C-terminal S-isoprenylcysteine carboxyl O-methyltransferase activity | |
Biological Process | flower development | |
Biological Process | methylation | |
Biological Process | negative regulation of abscisic acid-activated signaling pathway | |
Biological Process | shoot system development |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameProtein-S-isoprenylcysteine O-methyltransferase B
- EC number
- Short namesAtICMTB
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageEukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis
Accessions
- Primary accessionQ93W54
- Secondary accessions
Proteomes
Organism-specific databases
Genome annotation databases
Subcellular Location
UniProt Annotation
GO Annotation
Endoplasmic reticulum membrane ; Multi-pass membrane protein
Features
Showing features for transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Transmembrane | 16-36 | Helical | ||||
Sequence: MFLAIIFFHTSEYILAIAIHG | ||||||
Transmembrane | 52-72 | Helical | ||||
Sequence: ALAMLISVLEYIAEIVFFPGL | ||||||
Transmembrane | 81-101 | Helical | ||||
Sequence: FGLTMIILGEILRKTAIITAG | ||||||
Transmembrane | 140-160 | Helical | ||||
Sequence: VGTQVMLCNPISAIAFAVVVW |
Keywords
- Cellular component
Phenotypes & Variants
Disruption phenotype
Plants lacking ICMTA and ICMTB have altered phyllotaxis, fasciated stems and development of axillary flowers.
Variants
We now provide the "Disease & Variants" viewer in its own tab.
The viewer provides 15 variants from UniProt as well as other sources including ClinVar and dbSNP.
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000356250 | 1-197 | Protein-S-isoprenylcysteine O-methyltransferase B | |||
Sequence: MTEIFSDTGFRQLTQMFLAIIFFHTSEYILAIAIHGASKVTLSSLLISKHYALAMLISVLEYIAEIVFFPGLKQHWWISNFGLTMIILGEILRKTAIITAGRSFTHLIKIRREEHHKLVTEGVYQIMRHPSYSGFLIWSVGTQVMLCNPISAIAFAVVVWRFFAERIPYEEHYLKQFFGRQYVEYAQRVPSGVPFVN |
Proteomic databases
Expression
Tissue specificity
Expressed in flowers, stems, leaves, roots and siliques. Detected in apices and vascular tissues of leaves and roots, in the stigma and in the filaments and anthers of stamen. Not found in petioles or hypocotyls.
Induction
Not induced by abscisic acid or auxin.
Gene expression databases
Structure
Family & Domains
Sequence similarities
Belongs to the class VI-like SAM-binding methyltransferase superfamily. Isoprenylcysteine carboxyl methyltransferase family.
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length197
- Mass (Da)22,766
- Last updated2001-12-01 v1
- Checksum54EBEBEBADBF97DB
Sequence caution
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AL392174 EMBL· GenBank· DDBJ | CAC08334.1 EMBL· GenBank· DDBJ | Genomic DNA | Sequence problems. | |
CP002688 EMBL· GenBank· DDBJ | AED91285.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
CP002688 EMBL· GenBank· DDBJ | ANM69655.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AY035028 EMBL· GenBank· DDBJ | AAK59533.1 EMBL· GenBank· DDBJ | mRNA | ||
AY059102 EMBL· GenBank· DDBJ | AAL15208.1 EMBL· GenBank· DDBJ | mRNA |