The leucine-rich repeat protein PRELP binds fibroblast cell-surface proteoglycans and enhances focal adhesion formation
The leucine-rich repeat protein PRELP binds fibroblast cell-surface proteoglycans and enhances focal adhesion formation
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DOI：
10.1042/bcj20160095
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发表时间：
2016-05-01
影响因子：
4.1
通讯作者：
Aspberg, Anders
中科院分区：
文献类型：
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作者：
Bengtsson, Eva;Lindblom, Karin;Aspberg, Anders
PRELP（proline/casein-rich end leucine-rich repeat protein）是结缔组织中细胞外基质蛋白的富含亮氨酸重复序列（leucine-rich repeat，LRR）家族的成员。与该家族的其他成员相比，PRELP的N-末端结构域具有高含量的脯氨酸和带正电荷的氨基酸。该结构域先前已被证明结合软骨细胞并抑制破骨细胞分化。在本研究中，我们表明，PRELP介导的细胞粘附结合细胞表面糖胺聚糖（GAG）。因此，大鼠皮肤成纤维细胞（RSFs）绑定到全长PRELP和单独的PRELP的N-末端部分，但不截断PRELP缺乏带正电荷的N-末端区域。通过加入可溶性肝素或硫酸乙酰肝素（HS），通过阻断成纤维细胞的硫酸化或通过用软骨素酶和肝素酶的组合处理细胞来抑制细胞附着到PRELP。使用亲和层析，我们确定syndecan-1，syndecan-4和磷脂酰肌醇蛋白聚糖-1作为细胞表面蛋白聚糖（PG）结合到N-末端部分的PRELP。最后，我们表明，N-末端结构域的PRELP与整合素结合结构域的纤连蛋白，但无论是单独的片段，诱导成纤维细胞粘着斑形成。这些研究结果提供了支持的作用的N-末端区域的PRELP作为一个重要的调节细胞粘附和行为，这可能是重要的病理条件。
PRELP (proline/arginine-rich end leucine-rich repeat protein) is a member of the leucine-rich repeat (LRR) family of extracellular matrix proteins in connective tissue. In contrast with other members of the family, the N-terminal domain of PRELP has a high content of proline and positively charged amino acids. This domain has previously been shown to bind chondrocytes and to inhibit osteoclast differentiation. In the present study, we show that PRELP mediates cell adhesion by binding to cell-surface glycosaminoglycans (GAGs). Thus, rat skin fibroblasts (RSFs) bound to full-length PRELP and to the N-terminal part of PRELP alone, but not to truncated PRELP lacking the positively charged N-terminal region. Cell attachment to PRELP was inhibited by addition of soluble heparin or heparan sulfate (HS), by blocking sulfation of the fibroblasts or by treating the cells with a combination of chondroitinase and heparinase. Using affinity chromatography, we identified syndecan-1, syndecan-4 and glypican-1 as cell-surface proteoglycans (PGs) binding to the N-terminal part of PRELP. Finally, we show that the N-terminal domain of PRELP in combination with the integrin-binding domain of fibronectin, but neither of the fragments alone, induced fibroblast focal adhesion formation. These findings provide support for a role of the N-terminal region of PRELP as an important regulator of cell adhesion and behaviour, which may be of importance in pathological conditions.