beta I + II Tubulin Products

Tubulin is the major building block of microtubules. This intracellular, cylindrical filamentous structure is present in almost all eukaryotic cells. Microtubules function as structural and mobile elements in mitosis, intracellular transport, flagellar movement and the cytoskeleton. Except in the simplest eukaryotes, tubulin exists in all cells as a mixture of similar but not identical sets of alpha and beta tubulin polypeptides. Within either family, individual subunits diverge from each other (both within and across species) at less than 10% of the amino acid positions. The most extreme diversity is localized to the carboxy-terminal 15 residues. For beta-tubulin, five evolutionarily conserved isotype clones have been identified. These are almost totally conserved in the subunits utilized in the same cell types of different species with the exception of the hematopoietic beta tubulin which is highly divergent in sequence and which is not conserved between species. Research has been centered around the hypothesis that these beta tubulin isotypes contribute to unique functional properties. It has been reported that the different isotypes of tubulin differ from each other in their ability to polymerize into microtubules.