Figure 2.

The Singly Lipidated Polybasic Terminus (SLIPT) non-canonical calmodulin-binding motif. Top: sequence of the myristoylated SLIPT motif in CAP23/NAP22 and the farnesylated SLIPT in KRAS4b. Middle: Ribbon models of Ca²⁺-calmodulin in complex with a myristoylated N-terminal peptide of CAP23/NAP22 (PDB accession code 1L7Z) and farnesyl cysteine methyl ester (FCME), representing the farnesylated C-terminal residue of KRAS4b (PDB 6OS4). The calmodulin C-terminal and N-terminal lobes are coloured brown and blue, respectively, with lipids in green and peptidyl moieties of the targets in red. Bottom: Space filling models of the N-terminal and C-terminal lobes of calmodulin showing how the SLIPT motifs interact. Right panel: Sequences of SLIPT motif sequences from KRAS4b, other small GTPase proteins and myristoylated proteins. Sequences of RAS isoforms lacking SLIPT motifs are also shown. Reported phosphorylation sites are red, palmitoylation sites are green and basic residues are highlighted in blue. Myr, Myristoyl; farn, farnesyl; gg, geranylgeranyl.