FKBP12: A partner of Snx10 required for vesicular trafficking in osteoclasts
FKBP12: A partner of Snx10 required for vesicular trafficking in osteoclasts
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DOI：
10.1002/jcb.28606
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发表时间：
2019-08-01
影响因子：
4
通讯作者：
Morse, Leslie R.
中科院分区：
文献类型：
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作者：
Battaglino, Ricardo A.;Jha, Prakash;Morse, Leslie R.
破骨细胞采用高度专门化的细胞内转运控制来进行骨吸收和细胞器内稳态。分类Nexin Snx10是一种(磷脂酰肌醇3-磷酸)PI3P结合蛋白，定位于破骨细胞早期的内小体。缺乏功能性Snx10的人和小鼠的破骨细胞功能严重失调。它们在内吞作用、细胞外酸化、褶皱边缘形成和骨吸收方面表现出明显的损害，表明Snx10调节膜运输。为了更好地了解SNx10如何调控破骨细胞的囊泡形成和运输，我们开始寻找Snx10的合作伙伴。我们进行了酵母双杂交筛选，鉴定出FKBP12。FKBP12表达于核因子kB配体刺激的RAW264.7单核细胞的受体激活剂，与Snx10共沉淀，并与Snx10共定位于破骨细胞。我们还发现FKBP12、Snx10和早期内体抗原1(EEA1)存在于相同的蔗糖梯度离心法获得的亚细胞组分中，这证实了FKBP12在早期内体中的定位。综上所述，这些结果表明Snx10和FKBP12是配对的，并提示Snx10和FKBP12通过合成参与内体/溶酶体动态平衡的调节。这些发现可能建议通过靶向破骨细胞膜运输的关键步骤来控制骨丢失的新的治疗方法。
Osteoclasts employ highly specialized intracellular trafficking controls for bone resorption and organelle homeostasis. The sorting nexin Snx10 is a (Phosphatidylinositol 3-phosphate) PI3P-binding protein, which localizes to osteoclast early endosomes. Osteoclasts from humans and mice lacking functional Snx10 are severely dysfunctional. They show marked impairments in endocytosis, extracellular acidification, ruffled border formation, and bone resorption, suggesting that Snx10 regulates membrane trafficking. To better understand how SNx10 regulates vesicular formation and trafficking in osteoclasts, we set out on a search for Snx10 partners. We performed a yeast two-hybrid screening and identified FKBP12. FKBP12 is expressed in receptor activator of nuclear factor kB ligand-stimulated RAW264.7 monocytes, coimmunoprecipitates with Snx10, and colocalizes with Snx10 in osteoclasts. We also found that FKBP12, Snx10, and early endosome antigen 1 (EEA1) are present in the same subcellular fractions obtained by centrifugation in sucrose gradients, which confirms localization of FKBP12 to early endosomes. Taken together, these results indicate that Snx10 and FKBP12 are partners and suggest that Snx10 and FKBP12 are involved in the regulation of endosome/lysosome homeostasis via the synthesis. These findings may suggest novel therapeutic approaches to control bone loss by targeting essential steps in osteoclast membrane trafficking.