The molecular mechanism of organelle transport along microtubules: The identification and characterization of KIFs (Kinesin superfamily proteins)

In the cells various kinds of organelles are transported and distributed to their proper destinations in the cell. Organelle transports are very important for cellular morphogenesis and functions, with the conveying and targeting of essential materials to their correct destination being conducted, often at considerable velocities. Recently we have identified at least 10 new microtubule-associated motor proteins named as KIFs (kinesin superfamily proteins). Their characterization reveals that each member can convey a specific organelle or cargo, although there is some redundancy. It has also become clear that there are distinct subclasses of KIFs that form monomeric, heterodimeric and homodimeric motors. Molecular cell biological approaches combining multidiciplinary methods such as new electron microscopy, biochemistry, immunocytochemistry, biophysics, molecular biology and molecular genetics have revealed precise mechanisms of organelle transports in the cells by KIFs.