The motor domain is localized to the N terminus, and theKIF26A

in all KIFs, exhibiting a high degree of homology and containing a microtubule-binding and an ATP-binding sequence. However, outside the motor domain, each KIF possesses a unique sequence. The diversity of these cargo-binding domains plays a role in the mechanisms of action, as well as binding regulation (Hirokawa and Takemura, 2005). A total of 45 murine and human KIFs have been identified and classified into 14 large families— termed kinesin 1 to 14 (Miki et al., 2001; Lawrence et al., 2004). Here, we identified Kinesin superfamily protein 26A (KIF26A), a new member of the KIFs belonging to the kinesin 11 subfamily (Miki et al., 2001; Lawrence et al., 2004). KIF26A has a divergent motor domain that exhibits microtubule-binding activity but lacks ATPase activity, which indicates a function other than cargo transport. To examine the role of KIF26A in vivo, we gener-tion for KIF26A as a negative regulator of GDNF-Ret signaling in ENS development