Fig. 10. KIFC2 is highly enriched and functional on endocytic vesicles. (A) Fifteen micrograms of total protein from rat liver homogenate, PNS, cytosol, S-200 fraction and purified endocytic vesicles were subjected to 10-20% gradient SDS-Page and immunoblotted with antibody to KIFC2, as described in Materials and Methods. (B,C) MT-bound endocytic vesicles were incubated for 6 minutes with buffer alone or buffer containing affinity purified anti-KIFC2, following which 50 µM ATP was added to produce vesicle motility. In some studies, fluorescent polarity marked microtubules were used (C). The bars in panel B indicate the percentage of MT-bound vesicles that moved upon ATP addition. The number of motile vesicles versus the total number of MT-bound vesicles that were examined is in parentheses. The bars in panel C indicate the percentage of vesicles that moved upon ATP addition in the minus-end or plus-end directions. For each experiment, the number of motile vesicles in either direction versus the total number of motile vesicles that were examined is in parentheses. *P<0.002 versus control.