Key Concepts of Section 18.3

• Microtubules can be stabilized by side-binding microtubule-associated proteins (MAPs) (see Figure 18-13).

• Some MAPs, called +TIPs, bind selectively to growing (+) ends of microtubules and can alter the dynamic properties of the microtubule or attach components of the cell to the searching (+) end of the microtubule (see Figure 18-14).

• Microtubule ends can be destabilized by some proteins, such as the kinesin-13 family of proteins and Op18/stathmin, to enhance the frequency of catastrophes (see Figure 18-15).