Dynamic localization of α-tubulin acetyltransferase ATAT1 through the cell cycle in human fibroblastic KD cells

Abstract

Acetylation of α-tubulin is a well-studied posttranscriptional modification, which is mostly catalyzed by α-tubulin N-acetyltransferase (ATAT1). ATAT1 possibly affects various cellular functions related with microtubules, such as intracellular transport, cell motility, cilia formation, and neuronal signaling. Here, we analyzed the subcellular localization of immunolabeled ATAT1 in human fibroblast KD cells through the cell cycle using confocal laser scanning microscopy. ATAT1 dramatically changed its localization through the cell cycle, depending on the mitotic phase. In interphase, immunolabeled ATAT1 was observed in centrioles, nuclei, and basal bodies if the cells projected primary cilia. ATAT1 was intensely detected as clusters in the nuclei in the G1-G2 phase. In telophase, ATAT1 colocalized with chromatids and spindle poles, and ultimately migrated to the daughter nucleus, newly synthesized centrioles, and midbody. The nucleolus is a core region of ribosomal RNA transcription, and the midbody is associated with severing and depolymerizing of microtubules in the stembody. The specific distributions of ATAT1 through the cell cycle suggest multiple functions of ATAT1, which could include acetylation of microtubules, RNA transcription activity, severing microtubules, and completion of cytokinesis.

Cep97 Is Required for Centriole Structural Integrity and Cilia Formation in Drosophila

“…Remarkably, perturbation of components of the microtubule acetylation machinery (Sirt2, Hdac6, and Atat1) largely phenocopies loss of Cep97. All three components have been localized to stable microtubules, including those at centrioles [43,55,56]. We could recapitulate this localization by overexpression of GFP transgenes in Drosophila S2 cells (Figure S4E).…”

Cep97 Is Required For Centriole Structural Integrity And Cilia Formation In Drosophila

“…Remarkably, perturbation of components of the microtubule acetylation machinery (Sirt2, as well as another deacetylase Hdac6 and the acetyltransferase Atat1) largely phenocopies the effect of loss of Cep97. All three components have been localized to stable microtubules, including those at centrioles [42, 54,55]. The most simple explanation, then, is that Cep97 regulates this machinery at centrioles to stabilize centriolar microtubules and confer on them their remarkable lack of dynamics, so different from that of other cytoplasmic microtubules ( Fig.…”

A phospho-regulated signal motif determines subcellular localization of α-TAT1 for dynamic microtubule acetylation

“…Specifically, our study shows a role of CDKs, PKA and CK2 in coordinating spatial distribution of α-TAT1. Such phospho-regulation of α-TAT1 provides a possible mechanism for the changes in α-TAT1 localization and microtubule acetylation observed at different stages of the cell cycle 72 . We identified Threonine-322 to be a putative binding site for 14-3-3 proteins and demonstrated that α-TAT1 binds to 14-3-3-β and 14-3-3-ζ proteins.…”

“…Specifically, our study shows a role of CDK1 and CK2 in coordinating spatial distribution of α-TAT1 and downstream MT acetylation to mediate cell proliferation and DNA damage response. Such phospho-regulation of α-TAT1 provides a possible mechanism for the changes in α-TAT1 localization and microtubule acetylation observed at different stages of the cell cycle 69 . While MT acetylation plays a critical role in DNA damage response, whether Threonine-322 mediates DNA damage response through modulating MT acetylation levels or by additional means remains to be examined.…”