Microtubule - Nucleation and Growth

Nucleation and Growth

Microtubules are often nucleated at a dedicated microtubule-organizing center. Contained within the MTOC is another type of tubulin, γ-tubulin, which is distinct from the α and β subunits, which compose the microtubules themselves. The γ-tubulin combines with several other associated proteins to form a circular structure known as the "γ-tubulin ring complex" (γ-TuRC). This complex acts as a scaffold for α/β tubulin dimers to begin polymerization; it acts as a cap of the (−) end while microtubule growth continues away from the MTOC in the (+) direction.