Dacheux Denis, Roger Benoit, Bosc Christophe, Landrein Nicolas, Roche Emmanuel, Chansel Lucie, Trian Thomas, Andrieux Annie, Papaxanthos-Roche Aline, Marthan Roger, Robinson Derrick R, Bonhivers Mélanie
University Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France Institut Polytechnique de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
University Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
J Cell Sci. 2015 Apr 1;128(7):1294-307. doi: 10.1242/jcs.155143. Epub 2015 Feb 11.
Cilia and flagella are microtubule-based organelles present at the surface of most cells, ranging from protozoa to vertebrates, in which these structures are implicated in processes from morphogenesis to cell motility. In vertebrate neurons, microtubule-associated MAP6 proteins stabilize cold-resistant microtubules through their Mn and Mc modules, and play a role in synaptic plasticity. Although centrioles, cilia and flagella have cold-stable microtubules, MAP6 proteins have not been identified in these organelles, suggesting that additional proteins support this role in these structures. Here, we characterize human FAM154A (hereafter referred to as hSAXO1) as the first human member of a widely conserved family of MAP6-related proteins specific to centrioles and cilium microtubules. Our data demonstrate that hSAXO1 binds specifically to centriole and cilium microtubules. We identify, in vivo and in vitro, hSAXO1 Mn modules as responsible for microtubule binding and stabilization as well as being necessary for ciliary localization. Finally, overexpression and knockdown studies show that hSAXO1 modulates axoneme length. Taken together, our findings suggest a fine regulation of hSAXO1 localization and important roles in cilium biogenesis and function.
纤毛和鞭毛是以微管为基础的细胞器,存在于从原生动物到脊椎动物的大多数细胞表面,这些结构参与了从形态发生到细胞运动等过程。在脊椎动物神经元中,微管相关的MAP6蛋白通过其Mn和Mc模块稳定抗冷微管,并在突触可塑性中发挥作用。尽管中心粒、纤毛和鞭毛具有冷稳定微管,但尚未在这些细胞器中鉴定出MAP6蛋白,这表明有其他蛋白质在这些结构中发挥这一作用。在这里,我们将人类FAM154A(以下简称hSAXO1)鉴定为广泛保守的特定于中心粒和纤毛微管的MAP6相关蛋白家族的首个人类成员。我们的数据表明,hSAXO1特异性结合中心粒和纤毛微管。我们在体内和体外确定,hSAXO1的Mn模块负责微管结合和稳定,也是纤毛定位所必需的。最后,过表达和敲低研究表明,hSAXO1调节轴丝长度。综上所述,我们的研究结果表明hSAXO1的定位受到精细调控,并在纤毛的形成和功能中发挥重要作用。