DIDO3 Regulates Microtubule Stability at Transcriptional and Posttranslational Levels and is Needed for Fibroblast Adhesion and Movement

Microtubule (MT) dynamics are central to eukaryotic cell organization, intracellular transport, division, adhesion, polarization, and migration. Unbalanced MT stability is associated with metastasis and neurodegenerative diseases. We show that altered expression of death-inducer obliterator isoform 3 (DIDO3) restricts cell adhesion and motility. Fibroblasts with a DIDO3 C-terminal delection (DIDO3ΔCT) show i) MT bundling and looping, ii) failure to localize the tubulin plus-end binding protein CLASP2 to the membrane, iii) deregulated tubulin-actin-binding proteins EB1, GAS2L1, and DNM1 downstream of GSK3β, and iv) transcriptionally deregulated cytoskeletal- and non-cytoskeletal-coding genes (Gas2l1, Dnm1, Tubb4a, Obsl1 and Sema7a, Lgals3bp, Cct3, respectively) associated to cell migration, adhesion, immune responses, and tubulin-actin folding. DIDO3ΔCT deletion delocalizes the GSK3β-interacting protein ninein and prevents MT growth from the centrosome. DIDO3 expression in DIDO3ΔCT fibroblasts largely reestablishes the normal phenotype. Furthermore, DIDO3ΔCT B cells do not polarize the centrosome to the immunological synapse, a tubulin-dependent process. DIDO3CT overexpression induces tubulin stabilization and CLASP2 accumulation at the cell membrane. We propose a mechanism by which DIDO3 links transcriptional and posttranslational regulation of MT stability.