Regnard Catherine, Fesquet Didier, Janke Carsten, Boucher Dominique, Desbruyéres Elisabeth, Koulakoff Annette, Insina Christine, Travo Pierre, Eddé Bernard
Centre de Recherches de Biochimie Macromoléculaire, CNRS, 34293 Montpellier, France.
J Cell Sci. 2003 Oct 15;116(Pt 20):4181-90. doi: 10.1242/jcs.00743.
Polyglutamylation is a post-translational modification initially discovered on tubulin. It has been implicated in multiple microtubule functions, including neuronal differentiation, axonemal beating and stability of the centrioles, and shown to modulate the interaction between tubulin and microtubule associated proteins. The enzymes catalysing this modification are not yet known. Starting with a partially purified fraction of mouse brain tubulin polyglutamylase, monoclonal antibodies were raised and used to further purify the enzyme by immunoprecipitation. The purified enzyme complex (Mr 360x103) displayed at least three major polypeptides of 32, 50 and 80x103, present in stochiometric amounts. We show that the 32x103 subunit is encoded by the mouse gene GTRGEO22, the mutation of which has recently been implicated in multiple defects in mice, including male sterility. We demonstrate that this subunit, called PGs1, has no catalytic activity on its own, but is implicated in the localisation of the enzyme at major sites of polyglutamylation, i.e. neurones, axonemes and centrioles.
多聚谷氨酰胺化是一种最初在微管蛋白上发现的翻译后修饰。它与多种微管功能有关，包括神经元分化、轴丝摆动和中心粒的稳定性，并已显示出可调节微管蛋白与微管相关蛋白之间的相互作用。催化这种修饰的酶尚不清楚。从部分纯化的小鼠脑微管蛋白多聚谷氨酰胺酶组分开始，制备了单克隆抗体，并用于通过免疫沉淀进一步纯化该酶。纯化的酶复合物（分子量360×10³）显示出至少三种主要多肽，分子量分别为32×10³、50×10³和80×10³，且以化学计量的量存在。我们发现32×10³亚基由小鼠基因GTRGEO22编码，该基因的突变最近被认为与小鼠的多种缺陷有关，包括雄性不育。我们证明这个亚基，称为PGs1，自身没有催化活性，但与该酶在多聚谷氨酰胺化的主要位点，即神经元、轴丝和中心粒的定位有关。
