FNTB also known as FTβ is a key enzyme in the mevalonate-dependent prenylation pathway that covalently attaches a farnesyl isoprenoid to C-terminal CaaX motifs. FNTB plays a crucial role in post-translational modification of proteins through farnesylation, a process essential for proper localization and function of several key proteins, including nuclear lamins and oncogene p21Ras. This modification is vital for membrane association of these proteins, influencing their activity and interactions within the cell. The farnesyl transferase enzyme, consisting of a heterodimer of α and β subunits, facilitates attachment of farnesyl residues to specific cysteine residues in target proteins, thereby regulating various cellular processes such as signal transduction and cell division.