Tubulin Polymerization Promoting Protein (TPPP)

Seki et al. (1999) cloned p25 from a neuroblastoma cDNA library. The deduced 219-amino acid protein has a calculated molecular mass of about 24 kD. Human and bovine p25 share 90% amino acid identity. In contrast to the brain-specific expression of bovine p25, RT-PCR detected human p25 in all tissues examined.Martin et al. (2002) found that p24 associated with Gsk3 in microtubules from adult rat brain. p24 bound Gsk3 and inhibited its kinase activity at low magnesium concentrations. p24 was a poor substrate for Gsk3, but it could be phosphorylated by other protein kinases. Bovine Tppp inhibited mitotic spindle assembly and nuclear envelope breakdown following injection into Drosophila embryos. It did not affect other cellular events.