IIITubulin

IIItubulin, commonly referred to as beta-III tubulin, is a member of the beta-tubulin family that forms microtubules by heterodimerizing with alpha-tubulin. Microtubules are dynamic polymers that support cell shape, intracellular transport, and division. Beta-III tubulin is predominantly expressed in neurons of the developing and adult nervous system and serves as a widely used immunohistochemical marker of neuronal differentiation.

Biochemically, beta-tubulin isotypes, including beta-III, influence the properties of microtubules, such as dynamics, stability, and interactions with microtubule-associated proteins and motor proteins. The beta-III isotype may confer distinct polymerization characteristics compared with other isotypes, contributing to the specialized needs of neuronal microtubules.

The TUBB3 gene encodes beta-III tubulin. In humans, beta-III tubulin is found mainly in neurons but can be upregulated in certain non-neuronal cancers and other diseases.

Clinical relevance: Aberrant beta-III tubulin expression has been reported in various cancers and is frequently associated with resistance to microtubule-targeting chemotherapies, particularly taxanes, and with poorer prognosis in some tumor types. Consequently, beta-III tubulin is studied as a predictive biomarker and as part of disease profiling.

In research and diagnostics, antibodies against beta-III tubulin are used to identify neuronal differentiation and to study neural development, neurodegenerative processes, and tumor biology. Overall, IIItubulin plays a specialized role in neuronal cytoskeleton function and clinical oncology as a biomarker and potential therapeutic correlate.