Clathrin assembly protein CALM plays a critical role in KIT signaling by regulating its cellular transport from early to late endosomes in hematopoietic cells.
Clathrin assembly protein CALM plays a critical role in KIT signaling by regulating its cellular transport from early to late endosomes in hematopoietic cells.
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DOI：
10.1371/journal.pone.0109441
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Matsumura I
中科院分区：
文献类型：
--
作者：
Rai S;Tanaka H;Suzuki M;Ogoh H;Taniguchi Y;Morita Y;Shimada T;Tanimura A;Matsui K;Yokota T;Oritani K;Tanabe K;Watanabe T;Kanakura Y;Matsumura I
Calm与笼蛋白包裹的囊泡的形成有关，后者介导生长因子受体和营养物质的内吞作用和细胞内运输。我们以前发现，平静缺乏的小鼠患有严重的贫血，这是由于胞膜蛋白介导的未成熟红细胞转铁蛋白受体内吞作用受损所致。然而，CAMPE被认为可以调节造血干/祖细胞的生长和存活。因此，在这项研究中，我们重点研究了平静在这些细胞中的作用。在此，我们发现LINAGE−Sca-1+Kit+(LSK)细胞在Calm−/−小鼠胎肝中的数量减少。此外，Calm−/−LSK细胞的集落形成活性也受到抑制。此外，在Calm−/−LSK细胞中，干细胞因子、Flt3和Tpo依赖的生长受到严重损害，而它们可以在IL-3和IL-6的作用下正常增殖。我们还使用表达KIT的Calm−/−小鼠胚胎成纤维细胞(MEF)检测了KIT的细胞内转运。首先，我们通过内化实验证实了干细胞因子结合试剂盒的内吞作用在平静的−/−MEF中没有受到损害。然而，在平静的−/−MEF中，干细胞因子诱导的试剂盒运输从早期到晚期都受到严重损害。结果表明，虽然野生型(WT)MEF刺激30min后细胞内KIT消失，但在平静的−/−MEF中KIT仍然存在。此外，与WT MEF相比，静息−/−MEF中干细胞因子诱导的胞浆KIT的磷酸化增强并延长，导致Akt过度激活。在Calm−/−Kit+细胞中也观察到类似的Akt过度激活。这些结果表明，KIT的细胞内转运及其正常功能离不开CAMPE。此外，我们的数据表明，位于早期内小体的KIT可以激活下游分子作为信号内小体。由于KIT激活与某些恶性肿瘤的发病机制有关，因此操纵CAMAL功能将是一种有吸引力的治疗策略。
CALM is implicated in the formation of clathrin-coated vesicles, which mediate endocytosis and intracellular trafficking of growth factor receptors and nutrients. We previously found that CALM-deficient mice suffer from severe anemia due to the impaired clathrin-mediated endocytosis of transferrin receptor in immature erythroblast. However, CALM has been supposed to regulate the growth and survival of hematopoietic stem/progenitor cells. So, in this study, we focused on the function of CALM in these cells. We here show that the number of Linage−Sca-1+KIT+ (LSK) cells decreased in the fetal liver of CALM −/− mice. Also, colony forming activity was impaired in CALM−/− LSK cells. In addition, SCF, FLT3, and TPO-dependent growth was severely impaired in CALM−/− LSK cells, while they can normally proliferate in response to IL-3 and IL-6. We also examined the intracellular trafficking of KIT using CALM −/− murine embryonic fibroblasts (MEFs) engineered to express KIT. At first, we confirmed that endocytosis of SCF-bound KIT was not impaired in CALM −/− MEFs by the internalization assay. However, SCF-induced KIT trafficking from early to late endosome was severely impaired in CALM −/− MEFs. As a result, although intracellular KIT disappeared 30 min after SCF stimulation in wild-type (WT) MEFs, it was retained in CALM −/− MEFs. Furthermore, SCF-induced phosphorylation of cytosolic KIT was enhanced and prolonged in CALM −/− MEFs compared with that in WT MEFs, leading to the excessive activation of Akt. Similar hyperactivation of Akt was observed in CALM −/− KIT+ cells. These results indicate that CALM is essential for the intracellular trafficking of KIT and its normal functions. Also, our data demonstrate that KIT located in the early endosome can activate downstream molecules as a signaling endosome. Because KIT activation is involved in the pathogenesis of some malignancies, the manipulation of CALM function would be an attractive therapeutic strategy.
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血管内皮钙粘蛋白控制着细胞内室的VEGFR-2内在化和信号传导。
影响因子：
7.8
作者：
Lampugnani, Maria Grazia;Orsenigo, Fabrizio;Gagliani, Maria Cristina;Tacchetti, Carlo;Dejana, Elisabetta
通讯作者：
Dejana, Elisabetta
影响因子：
7.5
作者：
Kandachar, Vasundhara;Roegiers, Fabrice
通讯作者：
Roegiers, Fabrice
DOI：
10.1073/pnas.93.10.4804
发表时间：
1996-05-14
影响因子：
11.1
作者：
Dreyling, MH;MartinezCliment, JA;Bohlander, SK
通讯作者：
Bohlander, SK
影响因子：
4
作者：
Legendre-Guillemin, V;Wasiak, S;McPherson, PS
通讯作者：
McPherson, PS
影响因子：
64.8
作者：
Ford, MGJ;Mills, IG;McMahon, HT
通讯作者：
McMahon, HT