Cortical microtubule plus-end tracking protein required for cell morphogenesis and cell division. Promotes the stabilization of dynamic microtubules during mitosis. Regulates microtubule-cortex attachment, thereby contributing to self-organization of cortical microtubules and subsequent cell shape. Associates with cortical microtubules. Expressed at a low level in all tissues, mostly in young developing tissues. Various plant growth reductions (e.g. dwarf), cell form defects (e.g. reduced trichome branches number) and reduced mitotic activity. Less root cortical microtubule arrays hypersensitive to microtubule-destabilizing drugs. Aberrant microtubule preprophase bands, mitotic spindles, and phragmoplasts. Belongs to the CLASP family. An article reported an auxin transcription module controlling cell division plane rotation through CLASP; however, this paper was later retracted. Was originally thought to correspond to two different genes At2g20190 and At2g20200. Was originally thought to correspond to two different genes At2g20190 and At2g20200.