DBN1 and Familial prostate cancer: Drebrin binds to the microtubule +TIP protein EB3, but not to the closely related family member EB1, and this interaction couples dynamic microtubules to F-actin.2, 4, 24, 25 The drebrin-binding site is in the mid-region of EB3 and a construct encoding this region (EB3M) acts as a dominant-negative.2 The relative levels of EB1 and EB3 vary between prostate cancer cell lines (Figure 5a).