Carboxy-terminal motif such as -CC, -CXC, -CCX, -CCXX, -CCXXX, or -CXXX†
Geranylgeranyl(one or two moieties per substrate)
*C, cysteine; a1, and a2 are amino acids that are preferably aliphatic; the identity of a1 is more flexible than a2. X can be C, S, Q, A, M, T, H, V, N, F, G, or I for FT, or L, F, I, V, or M for GGT1 (in decreasing order of affinity). †Requires an escort protein such as REP1.