text: Oncoprotein 18/Stathmin has been shown to increase the frequency of catastrophe. Oncoprotein 18 (Op18) is a cytosolic protein that are found in abundance in either benign or malignant tumor site: through the complex timing of phosphorylation, this biomolecule regulates the depolymerization of microtubules. It has four sites of phosphorylation characterized by serine residues and are associated with cyclin-dependent protein kinases (CDKs): Ser16, Ser25, Ser38 and Ser63.  There are two different models that are in contention regarding the destabilization of microtubules due to Op18: the inhibition of tubulin dimer formation or a catastrophe phenomena. 
  The Kinesin-related protein XKCM1 stimulates catastrophes in Xenopus microtubules.
  The Kinesin-Related Protein 13 MCAK increases the frequency of catastrophe without affecting the promotion of microtubule growth.