SEPT8 is a member of the highly conserved septin family. Septins are 40- to 60-kD GTPases that assemble as filamentous scaffolds. They are involved in the organization of submembranous structures, in neuronal polarity, and in vesicle trafficking.

A conserved region found in all 3 variants contains the GTP-binding motif and is encoded by exons 3 through 10. Northern blot analysis detected expression of most SEPT8 variants in all brain and cardiovascular regions tested, as well as in prostate, testis, and ovary. Expression was highest in brain and aorta, and expression of each variant was tissue specific. Western blot analysis detected variant 1 at an apparent molecular mass of 58 kD in prostate, testis, and ovary.