Lysosomal integral membrane protein II binds thrombospondin-1 - Structure-function homology with the cell adhesion molecule CD36 defines a conserved recognition motif
Lysosomal integral membrane protein II binds thrombospondin-1 - Structure-function homology with the cell adhesion molecule CD36 defines a conserved recognition motif
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DOI：
10.1074/jbc.273.9.4855
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发表时间：
1998-02-27
影响因子：
4.8
通讯作者：
Silverstein, R
中科院分区：
文献类型：
--
作者：
Crombie, R;Silverstein, R
LIMPII（溶酶体整合膜蛋白II）是结构上与细胞表面糖蛋白CD 36相关的蛋白质家族之一。我们最近定义了一个单一的结构域的CD 36介导的结合粘附糖蛋白血小板反应蛋白-1（TSP 1）。已知CD 36-TSP 1相互作用在血小板-肿瘤和血小板-单核细胞粘附、血管生成和单核细胞摄取凋亡细胞中起作用。为了测试LIMPII是否也结合TSP 1，将对应于CD 36的TSP 1结合结构域的LIMPII肽表达为重组谷胱甘肽S-转移酶（GST）融合蛋白。在固相结合试验中，纯化的I-125-TSP 1以时间依赖性和可饱和的方式与固定的GST/LIMPII结合。过量未标记的TSP 1或EDTA的抑制证明了特异性。通过可溶性LIMPII融合蛋白、通过针对LIMPII肽的单特异性兔IgG和通过含有TSP 1结合结构域的CD 36融合蛋白特异性阻断LIMPII.TSP1复合物形成。Bowes黑色素瘤细胞转染嵌合LIMPII cDNA，靶向表达质膜赋予的能力，结合I-125-TSP 1，并坚持TSP 1包被的表面。这项研究定义了TSP 1的结合位点之间的LIMPII和CD 36保守，并表明，细胞表面LIMPII可能在某些情况下作为TSP 1的粘附受体的功能。计算机辅助同源性搜索表明，从CD 36家族成员的研究中鉴定的TSP 1识别基序可能在自然界中广泛表达。
LIMPII (lysosomal integral membrane protein II) is one of a family of proteins structurally related to the cell surface glycoprotein CD36. We recently defined a single structural domain on CD36 that mediates binding to adhesive glycoprotein thrombospondin-l (TSP1). The CD36-TSP1 interaction is known to play a role in platelet-tumor and platelet-monocyte adhesion, angiogenesis, and in monocyte uptake of apoptotic cells. To test whether LIMPII also binds TSP1, a LIMPII peptide corresponding to the TSP1 binding domain of CD36 was expressed as a recombinant glutathione S-transferase (GST) fusion protein. In solid phase binding assays, purified I-125-TSP1 bound to immobilized GST/LIMPII in a time-dependent and saturable manner. Inhibition by excess unlabeled TSP1 or EDTA demonstrated specificity. LIMPII.TSP1 complex formation was specifically blocked by soluble LIMPII fusion protein, by monospecific rabbit IgG directed against the LIMPII peptide and by CD36 fusion proteins containing the TSP1 binding domain. Transfection of Bowes melanoma cells with a chimeric LIMPII cDNA that targets expression to the plasma membrane conferred the ability to bind I-125-TSP1 and to adhere to TSP1-coated surfaces. This study defines a TSP1 binding site conserved between LIMPII and CD36 and suggests that cell surface LIMPII may function in some circumstances as an adhesion receptor for TSP1. Computer-assisted homology searches suggest that the TSP1 recognition motif identified from study of CD36 family members may be widely expressed in nature.