Tubulin beta-3 chain

Tubulin Beta-3 Chain

Differentiation of Human-Induced Pluripotent Stem Cells to GABAergic Neurons

The tubulin beta-3 chain is a protein that in humans is encoded by the TUBB3 gene. It is a member of the tubulin family, which are globular proteins that polymerize to form microtubules. Microtubules are a component of the cytoskeleton, providing structure and shape to eukaryotic cells, and are involved in various cellular processes including intracellular transport, cell division, and cell signaling.

Structure

Tubulin beta-3 chain is one of several beta-tubulin isotypes. It is composed of 450 amino acids and has a molecular weight of approximately 50 kDa. The protein has a highly conserved structure, characterized by a core of two beta sheets surrounded by alpha helices. The N-terminal domain binds to GTP, which is essential for the polymerization of tubulin into microtubules.

Function

The primary function of the tubulin beta-3 chain is to form microtubules by polymerizing with alpha-tubulin. Microtubules are dynamic structures that undergo rapid phases of growth and shrinkage, a process known as "dynamic instability." This dynamic nature is crucial for their role in mitosis, where they form the mitotic spindle that segregates chromosomes into daughter cells.

Tubulin beta-3 is particularly important in the nervous system, where it is involved in the development and maintenance of neurons. It is highly expressed in neuronal cells and is considered a marker for neuronal differentiation.

Clinical Significance

Mutations in the TUBB3 gene have been associated with various neurological disorders. These include congenital fibrosis of the extraocular muscles (CFEOM), a condition characterized by restricted eye movement and strabismus. Such mutations can disrupt the normal function of microtubules, leading to defects in neuronal migration and axon guidance.

Expression

Tubulin beta-3 is predominantly expressed in the central nervous system, but it is also found in other tissues. Its expression is tightly regulated during development, with high levels observed in developing neurons.

Related Pages

• Microtubule
• Cytoskeleton
• Neuronal differentiation
• TUBB3 gene