Involved in microtubule stabilization in many cell types, including neuronal cells. Specifically has microtubule cold stabilizing activity. Interacts with calmodulin (via C-terminus); the interaction is dependent on Ca(2+). Expressed in brain. Expressed in spinal chord. Isoform 2 expression is up-regulated in the prefrontal cortex (Brodmann's area 46) of patients with schizophrenia (postmortem brain study). Belongs to the STOP family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.