Protein farnesyltransferase subunit beta (IPR026872)

Short name: FTB

Overlapping homologous superfamilies

Family relationships



Protein farnesyltransferase (FTase) is an enzyme responsible for the posttranslational modification (farnesylation) of proteins carrying a carboxy-terminal CaaX motif, including Ras, Ras homologues, and other small G proteins. FTase catalyses the transfer of a farnesyl moiety from farnesyl pyrophosphate to the cysteine at the CaaX motif, where a is a small aliphatic amino acid and X is the carboxy-terminal residue [PMID: 10617635, PMID: 8424764]. Prenyltransferase employ a Zn2+ ion to alkylate a thiol group catalyzing the formation of thioether linkages between cysteine residues at or near the C terminus of protein acceptors and the C1 atom of isoprenoid lipids. FTase attaches a 15-carbon farnesyl group to the cysteine within the C-terminal CaaX motif of substrate proteins when X is Ala, Met, Ser, Cys or Gln [PMID: 12135472, PMID: 12374986, PMID: 9657673].

FTase is a heterodimeric complex comprised of a regulatory alpha subunit shared with geranylgeranyltransferase I (also a CaaX prenyltransferase) and a unique catalytic beta subunit [PMID: 12702202]. FTase plays important roles in the growth and differentiation of eukaryotic cells. It is essential for embryonic proliferation, but dispensable for adult homeostasis [PMID: 15837621]. In plants, is involved in abscisic acid signal transduction, which modulates a variety of developmental processes and responses to environmental stress [PMID: 8703061]. In yeast, protein farnesylation is important for maintaining normal cell morphology [PMID: 10617635] and for cell cycle progression [PMID: 11580838].

GO terms

Biological Process

GO:0018343 protein farnesylation

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005965 protein farnesyltransferase complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.