Credit: Trotman Lab, CSHL
Postdoctoral researchers Muhan Chen, Dawid G. Nowak and others in the Trotman lab at CSHL may have solved a mystery about prostate cancer: why some patients appear to have low levels of the powerful tumor-suppressing protein PTEN and yet have no mutations in the gene that encodes the protein. The answer is implied in this image. In a sample of mouse prostate tissue on the way to becoming cancerous, they show one area in which PTEN protein levels are high (Area 1, yellow dashes) and a nearby area (Area 2, red dashes) where they are low. Where PTEN is low, so are levels of a protein called Importin 11 (Ipo11); where PTEN is abundant, so too is Ipo11. Ipo11 saves PTEN proteins marked for destruction by carrying them into the cell nucleus, perhaps in this way forming a "reservoir" and saving PTEN for future use in the battle against the emerging tumor. When Ipo11 is missing, cancer progression is promoted.