Endocytosis of the dermatan sulfate proteoglycan decorin utilizes multiple pathways and is modulated by epidermal growth factor receptor signaling
Endocytosis of the dermatan sulfate proteoglycan decorin utilizes multiple pathways and is modulated by epidermal growth factor receptor signaling
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DOI：
10.1016/j.biochi.2006.12.012
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发表时间：
2007-05-01
期刊：
影响因子：
3.9
通讯作者：
Goette, Martin
中科院分区：
文献类型：
--
作者：
Feugaing, David Denis Sofeu;Tammi, Raija;Goette, Martin
人皮肤成纤维细胞通过受体介导的内吞作用有效地内化基质因子核心蛋白聚糖，然而，对其胞内运输途径直至溶酶体降解知之甚少。在体外系统测量的吸收和降解的[S-35]硫酸盐标记的核心蛋白聚糖，胞吞作用被阻断46%时，网格蛋白装配/拆卸使用氯丙嗪抑制。EGF受体信号传导的药理学抑制导致核心蛋白聚糖摄取减少34%，而IGF受体的抑制没有影响。使用共聚焦免疫荧光显微镜，我们确定只有约5-10%的内化核心蛋白聚糖与EGFR共定位。因此，摄取依赖于EGFR信号传导，而不是沿着相同途径沿着运输。核心蛋白聚糖通过早期内体运输到溶酶体，因为超过50%的核心蛋白聚糖与EEA 1共定位。此外，渥曼青霉素对内体融合的抑制引起核心蛋白聚糖内吞作用的显著抑制。网格蛋白结合的Hrs蛋白的过表达，以前已经被证明可以抑制EGFR的降解，阻断了核心蛋白聚糖的降解。胆固醇消耗菲律宾抑制摄取核心蛋白聚糖的34%，然而，几乎没有发现核心蛋白聚糖和小窝蛋白-1之间的细胞内共定位。联合使用菲律宾和氯丙嗪有一个加性抑制作用的核心蛋白聚糖的内吞作用。此外，氯丙嗪将核心蛋白聚糖从氯丙嗪敏感途径转移到另一种摄取途径。排除CD 44/透明质酸途径作为核心蛋白聚糖的内吞途径。我们的观察结果表明，核心蛋白聚糖是采取了一个以上的内吞途径。值得注意的是，脂筏依赖性EGFR信号调节核心蛋白聚糖摄取，表明存在潜在的反馈调节机制，用于核心蛋白聚糖介导的信号转导事件的脱敏。(C)2007年，Elsevier Masson SAS。All rights reserved.
Human skin fibroblasts efficiently internalize the matrikine decorin by receptor-mediated endocytosis, however, very little is known about its intracellular trafficking routes up to lysosomal degradation. In an in vitro system measuring uptake and degradation of [S-35]sulfate-labeled decorin, endocytosis was blocked by 46% when clathrin assembly/disassembly was inhibited using chlorpromazine. Pharmacological inhibition of EGF receptor signaling caused 34% reduction of decorin uptake, whereas inhibition of the IGF receptor had no effect. Using confocal immunofluorescence microscopy, we determined that only about 5-10% of internalized decorin colocalized with the EGFR. Thus, uptake depends on EGFR signaling rather than trafficking along the same pathway. Decorin passes through early endosomes towards trafficking to lysosomes, since more than 50% of decorin colocalized with EEA1 Moreover, inhibition of endosomal fusion by wortmannin caused a profound inhibition of decorin endocytosis. Overexpression of the clathrin-binding Hrs protein, which has previously been shown to inibit EGFR degradation blocked the degradation of decorin. Cholesterol depletion by filipin inhibited uptake of decorin by 34%, however, nearly no intracellular colocalization was found between decorin and caveolin-1. The combined use of filipin and chlorpromazine had an additive inhibitory effect on decorin endocytosis. Moreover, chlorpromazine diverted decorin from the chlorpromazine-sensitive pathway to an alternative uptake route. The CD44/hyaluronan pathway was excluded as an endocytic route for decorin. Our observations indicate that decorin is taken up by more than one endocytic pathway. Of note, lipid-raft-dependent EGFR signaling modulates decorm uptake, suggesting the presence of a potential feedback regulation mechanism for desensitization of signaling events mediated by decorin. (C) 2007 Elsevier Masson SAS. All rights reserved.