Involved in the control of the dynamic organization of the cortical cytoskeleton. May play a role in the organization of microtubule arrays at the centrosome through interaction with centrin 1 (CEN1). Interacts with CEN1, LNG1/TRM2 and LNG2/TRM1 (via C-terminus). Localizes to cytoplasm and cortical cytoskeletal structures, including the preprophase band and the interphase microtubule arrays (PubMed:18757558). Recruited to cytoskeletal structures by LNG2/TRM1 (PubMed:22286137). Extreme defects in morphogenesis, positioning of mitotic planes and cellular organization due to dysfunction of the cortical cytoskeleton and absence of the preprophase band of microtubules. In the ton1 insertional mutant, the two highly similar genes in tandem, TON1A and TON1B are simultaneously disrupted.