Welcome to the Kinesin Nomenclature Information Resource

EXAMPLE PROBLEMS

Hundreds of kinesins have been named using differing criteria, making scientific communication difficult at best. A case in point is the heavily studied KinI family (also called MCAK/Kinesin-13), which was initially named to emphasize the internal position of the motor domain relative to the full-length protein sequence (see Figure 1 below). Most KinI/MCAK/Kinesin-13 family members are thought to depolymerize microtubules (Desai et al., 1999), but not all kinesins that depolymerize microtubules belong to the KinI/MCAK/Kinesin-13 family. C-Terminal/Kinesin-14 family members, initially called KAR3 motors after the founding member of the family, also have been shown to depolymerize microtubules (Endow et al., 1994; Severin et al., 2001). Likewise, members of the Kinesin-8 family may induce microtubule depolymerization, because deletion of these genes leads to microtubule elongation in vivo (Cottingham et al., 1999; West et al., 2001). Fission yeast Kinesin-8 family members Klp5 and Klp6 have been referred to as "KinI family proteins," presumably to emphasize their depolymerase activity (Garcia et al., 2002; Miller et al., 1998), despite the fact that the motors are essentially N-terminal (see Figure 1 below). In addition, primary structure in the motor domain and phylogenetic analysis do not support this assignment, and there is no direct evidence that members of the Kinesin-8 family induce microtubule disassembly. There also are many kinesin sequences with internal motor cores that fall into families other than MCAK/KinI/Kinesin-13, and these are unlikely to be depolymerases. Examples are Kinesin-4 family member C. elegans KLP-12, Kinesin-3 family member human CMKRP, and Kinesin-7 family member Ustilago maydis KIN1. Furthermore, the motor domain of KinI/MCAK/Kinesin-13 family member KinI from Plasmodium falciparum is essentially N-terminally positioned.

References



Figure 1. Average motor position for each kinesin family. See Table 1 for help deciphering family names used in this figure. To the right of each family name is a scaled diagram representing the family's average motor core location relative to the amino- and carboxy-termini of the protein. These average locations were determined for families 1-8, 10, 13, and 14 by calculating the mean lengths of the amino-terminal extension, motor, and carboxy-terminal extension for all full-length sequences from the Lawrence et al. dataset (2002). Example sequences shown in Table 1 were used for families 9, 11, and 12.