Talk about microtubule organizing centers.

Polymerization of microtubules is initiated by centers in the cell, they are named MTOCs which are the cetnrosomes and the basal bodies. Plant cells have no centriole but proteins of MTOCs are present in the nuclear envelope and in the cell cortex. They are responsible for the nucleation of microtubules and number, length, polarity, and number of protofilaments that make up their walls, as weel as time and location. All of them share a specific form of tubulin named Y-tubuiln (gamma).