The function of TUBB8 (tubulin beta 8 class VIII, ENSG00000261456) is as follows. Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin. TUBB8 has a key role in meiotic spindle assembly and oocyte maturation (PubMed:26789871, PubMed:34509376). {ECO:0000269|PubMed:26789871, ECO:0000269|PubMed:34509376}.