Kinesin motors: no strain, no gain

The processive movement of the dimeric motor protein kinesin 1 along microtubules requires communication between the two motor domains. Yildiz et al. (2008) now show that tension between the motor domains not only is necessary for normal processivity but also may be sufficient for motor motility under some conditions.     

Three wise centromere functions: see no error,hear no break,speak no delay

The main function of the centromere is to promote kinetochore assembly for spindle microtubule attachment. Two additional functions of the centromere, however, are becoming increasingly clear: facilitation of robust sister‐chromatid cohesion at pericentromeres and advancement of replication of centromeric regions. The combination of these three centromere functions ensures correct chromosome segregation during mitosis. Here, we review the mechanisms of the kinetochore–microtubule interaction, focusing on sister‐kinetochore bi‐orientation (or chromosome bi‐orientation). We also discuss the biological importance of robust pericentromeric cohesion and early centromere replication, as well as the mechanisms orchestrating these two functions at the microtubule attachment site.