低密度脂蛋白受体相关蛋白1(LRP1)的活性定位于不同的质膜微区。
The activities of LDL Receptor-related Protein-1 (LRP1) compartmentalize into distinct plasma membrane microdomains.
作者信息
Laudati Emilia, Gilder Andrew S, Lam Michael S, Misasi Roberta, Sorice Maurizio, Gonias Steven L, Mantuano Elisabetta
机构信息
Department of Pathology, University of California San Diego, La Jolla, CA, USA; Institute of Pharmacology, Catholic University Medical School, Rome, Italy.
Department of Pathology, University of California San Diego, La Jolla, CA, USA.
出版信息
Mol Cell Neurosci. 2016 Oct;76:42-51. doi: 10.1016/j.mcn.2016.08.006. Epub 2016 Aug 23.
LDL Receptor-related Protein-1 (LRP1) is an endocytic receptor for diverse ligands. In neurons and neuron-like cells, ligand-binding to LRP1 initiates cell-signaling. Herein, we show that in PC12 and N2a neuron-like cells, LRP1 distributes into lipid rafts and non-raft plasma membrane fractions. When lipid rafts were disrupted, using methyl-β-cyclodextrin or fumonisin B1, activation of Src family kinases and ERK1/2 by the LRP1 ligands, tissue-type plasminogen activator and activated α-macroglobulin, was blocked. Biological consequences of activated LRP1 signaling, including neurite outgrowth and cell growth, also were blocked. The effects of lipid raft disruption on ERK1/2 activation and neurite outgrowth, in response to LRP1 ligands, were reproduced in experiments with cerebellar granule neurons in primary culture. Because the reagents used to disrupt lipid rafts may have effects on the composition of the plasma membrane outside lipid rafts, we studied the effects of these reagents on LRP1 activities unrelated to cell-signaling. Lipid raft disruption did not affect the total ligand binding capacity of LRP1, the affinity of LRP1 for its ligands, or its endocytic activity. These results demonstrate that well described activities of LRP1 require localization of this receptor to distinct plasma membrane microdomains.
低密度脂蛋白受体相关蛋白1(LRP1)是多种配体的内吞受体。在神经元和类神经元细胞中,配体与LRP1结合会启动细胞信号传导。在此,我们表明在PC12和N2a类神经元细胞中,LRP1分布于脂筏和非脂筏质膜组分中。当使用甲基-β-环糊精或伏马菌素B1破坏脂筏时,LRP1配体组织型纤溶酶原激活剂和活化的α-巨球蛋白对Src家族激酶和ERK1/2的激活被阻断。LRP1信号激活的生物学后果,包括神经突生长和细胞生长,也被阻断。在原代培养的小脑颗粒神经元实验中,重现了脂筏破坏对LRP1配体诱导的ERK1/2激活和神经突生长的影响。由于用于破坏脂筏的试剂可能会对脂筏外的质膜组成产生影响,我们研究了这些试剂对与细胞信号传导无关的LRP1活性的影响。脂筏破坏不影响LRP1的总配体结合能力、LRP1对其配体的亲和力或其内吞活性。这些结果表明,LRP1的上述活性需要该受体定位于不同的质膜微区。