Membrane localization of membrane type 5 matrix metalloproteinase by AMPA receptor binding protein and cleavage of cadherins
Membrane localization of membrane type 5 matrix metalloproteinase by AMPA receptor binding protein and cleavage of cadherins
复制标题
DOI：
10.1523/jneurosci.3521-05.2006
复制
发表时间：
2006-02-22
影响因子：
5.3
通讯作者：
Ziff, EB
中科院分区：
文献类型：
--
作者：
Monea, S;Jordan, BA;Ziff, EB
基质金属蛋白酶（MMPs）被认为可以重塑神经元的细胞外环境。在这里，我们报告了金属蛋白酶膜5型MMP（MT5-MMP）与AMPA受体结合蛋白（ABP）和GRIP（谷氨酸受体相互作用蛋白）结合，这两种相关的突触后密度（PSD）PDZ（突触后密度-95/椎间盘大/椎间盘闭塞-1）结构域蛋白将AMPA受体靶向突触。MT5-MMP C末端结合ABP PDZ 5，两种蛋白质在异源细胞和神经元中共免疫沉淀和共定位。MT5-MMP定位于幼[ 2 - 5 d in vitro（DIV）]培养的胚胎海马神经元的生长锥尖端的丝状伪足，以及成熟（21 d in vitro）神经元的突触。它在突触体中的富集也表明在成熟脑中的突触定位。PDZ结合位点的缺失损害了MT5-MMP的膜运输，而分别与质膜或胞质溶胶相关的外源性ABP剪接形式与MT5-MMP共定位于突触棘中或将MT5-MMP招募到细胞内室。我们发现，内源性MT5-MMP被发现在培养的神经元和脑裂解物中的酶原的形式，激活弗林蛋白酶和降解的自动蛋白水解。我们还确定钙粘蛋白作为MT5-MMP底物。这些结果表明，ABP指导MT5-MMP蛋白水解活性的生长锥和神经元中的突触部位，在那里它可以通过钙粘蛋白或其他ECM或细胞粘附分子的蛋白水解来调节轴突寻路或突触重塑。
Matrix metalloproteinases ( MMPs) have been proposed to remodel the extracellular environment of neurons. Here, we report that the metalloproteinase membrane- type 5 MMP (MT5-MMP) binds to AMPA receptor binding protein (ABP) and GRIP ( glutamate receptor interaction protein), two related postsynaptic density (PSD) PDZ ( postsynaptic density-95/ Discs large/zona occludens-1) domain proteins that target AMPA receptors to synapses. The MT5-MMP C terminus binds ABP PDZ5 and the two proteins coimmunoprecipitated and colocalized in heterologous cells and neurons. MT5-MMP localized in filopodia at the tips of growth cones in young [ 2 - 5 d in vitro (DIV)] cultured embryonic hippocampal neurons, and at synapses in mature ( 21 DIV) neurons. Its enrichment in synaptosomes also indicated a synaptic localization in the mature brain. Deletion of the PDZ binding site impaired membrane trafficking of MT5-MMP, whereas exogenous ABP splice forms that are associated either with the plasma membrane or with the cytosol, respectively, colocalized with MT5-MMP in synaptic spines or recruited MT5-MMP to intracellular compartments. We show that endogenous MT5-MMP is found in cultured neurons and brain lysates in a proenzyme form that is activated by furin and degraded by auto-proteolysis. We also identify cadherins as MT5-MMP substrates. These results suggest that ABP directs MT5-MMP proteolytic activity to growth cones and synaptic sites in neurons, where it may regulate axon pathfinding or synapse remodeling through proteolysis of cadherins or other ECM or cell adhesion molecules.