Abrogation of Cbl-PI3K interaction increases bone formation and osteoblast proliferation.
Abrogation of Cbl-PI3K interaction increases bone formation and osteoblast proliferation.
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DOI：
10.1007/s00223-011-9531-z
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发表时间：
2011-11
影响因子：
4.2
通讯作者：
Sanjay, Archana
中科院分区：
文献类型：
--
作者：
Brennan, Tracy;Adapala, Naga Suresh;Barbe, Mary F.;Yingling, Vanessa;Sanjay, Archana
Cbl是一种衔接蛋白和E3连接酶，在影响各种细胞功能的几种信号通路中起着积极和消极的作用。酪氨酸737是Cbl所特有的，并被Src家族激酶磷酸化。磷酸化的CblY 737产生磷脂酰肌醇3激酶（PI 3 K）的p85调节亚基的结合位点，其也在骨稳态的调节中起重要作用。为了研究Cbl-PI 3 K相互作用在骨稳态中的作用，我们检查了基因敲入小鼠，其中Cbl上的PI 3 K结合位点由于酪氨酸737取代为苯丙氨酸而被消除（Cbl YF/YF，YF小鼠）。我们先前报道了这些小鼠中的骨体积由于破骨细胞功能降低而增加（Adapala等人，J Biol Chem 285：36745-36758）。在这里，我们报告说，YF小鼠也有增加骨形成和成骨细胞数量。在体外培养的骨髓源性YF成骨细胞表现出增加Col 1A的表达和他们的增殖也显着增强。此外，MC 3 T3-E1细胞的增殖增加后，用培养YF骨髓基质细胞产生的条件培养基处理。与野生型相比，YF骨髓基质细胞中基质衍生因子-1（SDF-1）的表达增加。与野生型相比，在YF骨髓基质细胞中观察到SDF-1和CXCR 4的免疫染色增加。用中和性抗SDF-1和抗CXCR 4抗体处理YF条件培养基减弱了MC 3 T3-E1细胞增殖。累积地，这些结果表明，Cbl-PI 3 K相互作用的消除扰乱骨稳态，影响破骨细胞功能和成骨细胞增殖。本文的在线版本（doi：10.1007/s 00223 -011-9531-z）包含补充材料，可供授权用户使用。
Cbl is an adaptor protein and E3 ligase that plays both positive and negative roles in several signaling pathways that affect various cellular functions. Tyrosine 737 is unique to Cbl and phosphorylated by Src family kinases. Phosphorylated CblY737 creates a binding site for the p85 regulatory subunit of phosphatidylinositol 3 kinase (PI3K) that also plays an important role in the regulation of bone homeostasis. To investigate the role of Cbl–PI3K interaction in bone homeostasis, we examined knock-in mice in which the PI3K binding site on Cbl was ablated due to the substitution of tyrosine 737 to phenylalanine (CblYF/YF, YF mice). We previously reported that bone volume in these mice is increased due to decreased osteoclast function (Adapala et al., J Biol Chem 285:36745–36758,). Here, we report that YF mice also have increased bone formation and osteoblast numbers. In ex vivo cultures bone marrow-derived YF osteoblasts showed increased Col1A expression and their proliferation was also significantly augmented. Moreover, proliferation of MC3T3-E1 cells was increased after treatment with conditioned medium generated by culturing YF bone marrow stromal cells. Expression of stromal derived factor-1 (SDF-1) was increased in YF bone marrow stromal cells compared to wild type. Increased immunostaining of SDF-1 and CXCR4 was observed in YF bone marrow stromal cells compared to wild type. Treatment of YF condition medium with neutralizing anti-SDF-1 and anti-CXCR4 antibodies attenuated MC3T3-E1 cell proliferation. Cumulatively, these results show that abrogation of Cbl–PI3K interaction perturbs bone homeostasis, affecting both osteoclast function and osteoblast proliferation. The online version of this article (doi:10.1007/s00223-011-9531-z) contains supplementary material, which is available to authorized users.
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影响因子：
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通讯作者：
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