Key microtubule-organizing protein that specifically binds the minus-end of non-centrosomal microtubules and regulates their dynamics and organization (PubMed:19508979, PubMed:24117850). Specifically recognizes growing microtubule minus-ends and stabilizes microtubules (By similarity). Acts on free microtubule minus-ends that are not capped by microtubule-nucleating proteins or other factors and protects microtubule minus-ends from depolymerization (By similarity). In contrast to CAMSAP2 and CAMSAP3, tracks along the growing tips of minus-end microtubules without significantly affecting the polymerization rate: binds at the very tip of the microtubules minus-end and acts as a minus-end tracking protein (-TIP) that dissociates from microtubules after allowing tubulin incorporation (By similarity). Through interaction with spectrin may regulate neurite outgrowth (PubMed:24117850). Interacts with spectrin via SPTBN1; the interaction is direct. Interacts with calmodulin; calcium-dependent it prevents interaction with spectrin. Associates with the minus-end of microtubules. In contrast to CAMSAP2 and CAMSAP3, does not form stretches of decorated microtubule minus-ends. In brain, specifically expressed in astrocytes (at protein level). First detected at E18, expression increases with growth and development in spite of a temporal decrease at P14. Still expressed in adult animals, in both the cerebrum and the cerebellum, although at lower levels in adults than in younger animals (at protein level). The CKK domain binds microtubules. Belongs to the CAMSAP1 family.