betaIIItubulin

Beta-III tubulin, also known as β3-tubulin, is a neuronal-specific member of the beta-tubulin family that forms heterodimers with alpha-tubulin to build microtubules. It is encoded by the TUBB3 gene in humans and contributes to the polymerization, stability, and dynamic remodeling of microtubules that support neurite outgrowth and axonal transport.

Expression of β3-tubulin is predominantly in neurons of the developing and adult nervous system; some studies report expression in neural crest derivatives and in certain non-neural tissues under pathological conditions. In histology, β3-tubulin is widely used as a neuronal marker; antibodies such as TUJ1 label β3-tubulin to identify neurons in brain tissue and cultured neurons.

Clinical relevance is observed in oncology, where TUBB3 overexpression has been linked with resistance to taxane chemotherapy and adverse prognosis in several cancer types, including non-small cell lung cancer and ovarian cancer; however results are context-dependent. β3-tubulin is also explored as a potential biomarker for tumor aggressiveness or therapy response, though its utility varies by cancer type and setting.

Genetics and biochemistry: The TUBB3 gene is located on chromosome 16q24.3 in humans. The protein has a distinctive C-terminal tail that modulates interactions with microtubule-associated proteins and drug-binding properties, contributing to microtubule dynamics in neurons. Expression is further regulated at the post-transcriptional level by microRNAs and through neuronal signaling pathways.