Motor Control: How Kinesins Drive Mitosis

One of the main components of the cytoskeleton is microtubules (MTs), which are comprised of heterodimers of a- and b-tubulin proteins. Tubulin can polymerize on both ends of MTs at different rates, where polymerization occurs more rapidly on the plus-end and is slower on the minus-end. The molecular motor families, kinesins and dyneins play a role in MT length by regulating the dynamic behavior of growth and shrinkage of MTs, known as dynamic instability¹. These motors work along MTs to provide cellular functions involving organelle transport, vesicle transport, meiosis, and mitosis.

Kinesins were first discovered in 1985 when it was observed that a new class of ATPases could cycle on and off microtubules and induce organelle movement along the axons of squid and vertebrate brain^2,3. Since then, 45 kinesin proteins have been identified in humans, with the Kinesins superfamily (KIF) organized into 14 recognized kinesin families⁴. Most kinesins have a plus-end directed motility, but motors in the kinesin-14 subfamily have a C-terminal motor and are minus-end directed. The general architecture of kinesins consists of three domains: 1) a catalytic motor or head domain that is well conserved within each kinesin family that can hydrolyze ATP and binds microtubules, 2) an adjacent neck domain that is involved in coiled-coil interactions and can organize the motor into higher-order oligomers, 3) On the opposite end of the protein is the tail domain, which can be highly divergent within a kinesin family, and is sometimes used to interact with cargo proteins, DNA, or regulatory domains^5–8. Below, we will look at recent findings on how kinesins affect the formation of the mitotic spindle and the organization of the chromosomes through the various stages of mitosis⁹.

Click to Read More

Also included in this newsletter:

• Motor Protein and Microtubule Tools
• Related Publications