Transforming properties of a Q18-->E mutation of the microtubule regulator Op18.


We have identified a somatic mutation in Op18 in a human esophageal adenocarcinoma. The mutant form of Op18 (M-Op18) was cloned and sequenced, revealing a substitution of a G for C at nucleotide 155, which results in a Q18-->E substitution in the protein. M-Op18 cDNA was expressed in NIH/3T3 cells, which resulted in foci formation and tumor growth in immunodeficient mice. Cell cycle analysis of M-Op18-expressing cells revealed a doubling in the percentage of cells in G2/M relative to cells overexpressing wild-type Op18, a decrease in M-Op18-specific phosphorylation, and alterations in tubulin ultrastructure in M-Op18-expressing cells. These results suggest that the somatic mutation identified in Op18 has profound effects on cell homeostasis that may lead to tumorigenicity.

  • Beer DG
  • Chang CL
  • Giordano TJ
  • Hanash SM
  • Hinderer R
  • Kuick R
  • Misek DE
Pub Med ID
Appears In
Cancer Cell, 2002, 2 (3)