Moore Carlene D, Thacker Erin E, Larimore Jennifer, Gaston David, Underwood Alison, Kearns Brian, Patterson Sean I, Jackson Trevor, Chapleau Chris, Pozzo-Miller Lucas, Theibert Anne
Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
J Cell Sci. 2007 Aug 1;120(Pt 15):2683-93. doi: 10.1242/jcs.006346. Epub 2007 Jul 17.
Centaurin alpha1 is an Arf GTPase-activating protein (GAP) that is highly expressed in the nervous system. In the current study, we show that endogenous centaurin alpha1 protein is localized in the synaptosome fraction, with peak expression in early postnatal development. In cultured dissociated hippocampal neurons, centaurin alpha1 localizes to dendrites, dendritic spines and the postsynaptic region. siRNA-mediated knockdown of centaurin alpha1 levels or overexpression of a GAP-inactive mutant of centaurin alpha1 leads to inhibition of dendritic branching, dendritic filopodia and spine-like protrusions in dissociated hippocampal neurons. Overexpression of wild-type centaurin alpha1 in cultured hippocampal neurons in early development enhances dendritic branching, and increases dendritic filopodia and lamellipodia. Both filopodia and lamellipodia have been implicated in dendritic branching and spine formation. Following synaptogenesis in cultured neurons, wild-type centaurin alpha1 expression increases dendritic filopodia and spine-like protrusions. Expression of a GAP-inactive mutant diminishes spine density in CA1 pyramidal neurons within cultured organotypic hippocampal slice cultures. These data support the conclusion that centaurin alpha1 functions through GAP-dependent Arf regulation of dendritic branching and spines that underlie normal dendritic differentiation and development.
Centaurin α1是一种在神经系统中高度表达的Arf GTP酶激活蛋白（GAP）。在本研究中，我们发现内源性Centaurin α1蛋白定位于突触体组分中，在出生后早期发育阶段表达达到峰值。在培养的解离海马神经元中，Centaurin α1定位于树突、树突棘和突触后区域。siRNA介导的Centaurin α1水平敲低或Centaurin α1的GAP失活突变体的过表达导致解离海马神经元中树突分支、树突丝状伪足和棘状突起受到抑制。在早期发育阶段，在培养的海马神经元中过表达野生型Centaurin α1可增强树突分支，并增加树突丝状伪足和片状伪足。丝状伪足和片状伪足均与树突分支和棘形成有关。在培养的神经元中发生突触形成后，野生型Centaurin α1的表达增加树突丝状伪足和棘状突起。GAP失活突变体的表达降低了培养的海马脑片培养物中CA1锥体神经元的棘密度。这些数据支持以下结论：Centaurin α1通过GAP依赖的Arf调节树突分支和棘发挥作用，而树突分支和棘是正常树突分化和发育的基础。
