Gene for an extracellular matrix receptor protein from Pneumocystis carinii.
Gene for an extracellular matrix receptor protein from Pneumocystis carinii.
复制标题
DOI：
10.1073/pnas.91.16.7440
复制
发表时间：
1994-08
影响因子：
11.1
通讯作者：
S. Narasimhan;M. Armstrong;K. Rhee;J. Edman;F. Richards;E. Spicer
中科院分区：
文献类型：
--
作者：
S. Narasimhan;M. Armstrong;K. Rhee;J. Edman;F. Richards;E. Spicer
许多微生物感染建立的最初和关键步骤是病原体与宿主细胞的附着。因此，卡氏肺孢子虫（Pc）粘附到I型肺细胞被认为是重要的诱导Pc肺炎。虽然细胞外基质（ECM）蛋白，如纤连蛋白和层粘连蛋白，已被牵连的过程中的Pc的附着到I型细胞的性质知之甚少。我们在这里报告的分离的Pc基因编码的受体蛋白，结合纤连蛋白和层粘连蛋白在体外。从Pc cDNA文库中分离编码Pc ECM受体的cDNA克隆，并基于与人结肠癌层粘连蛋白受体的序列同源性进行鉴定。对Pc基因组DNA的Southern杂交分析证实该cDNA是Pc来源的。对Pc总RNA的北方印迹分析显示，与ECM受体基因杂交的约1400个核苷酸的主要mRNA。从cDNA序列预测的ECM受体是295个氨基酸残基长，分子量为32.8 kDa。多肽的C-末端三分之一是高度负电荷的，而N-末端三分之二含有疏水片段，其可能在膜缔合中起作用。序列分析和N端与人结肠癌层粘连蛋白受体cDNA序列的比对支持Pc ECM受体cDNA克隆是全长克隆的结论。过表达的ECM受体蛋白在体外结合层粘连蛋白和纤连蛋白的Western印迹。过表达受体蛋白的抗体与总Pc细胞裂解物中的33 kDa蛋白相互作用。这些研究结果提出的可能性，Pc ECM受体蛋白可能介导的生物体的附着到I型肺细胞，因此，可能在Pc的发病机制中发挥至关重要的作用。
An initial and crucial step in the establishment of many microbial infections is the attachment of the pathogen to the host cells. Thus, adherence of Pneumocystis carinii (Pc) to type I pneumocytes is believed to be important in the induction of Pc pneumonia. Little is known about the nature of the attachment of Pc to type I cells, although extracellular matrix (ECM) proteins, such as fibronectin and laminin, have been implicated in the process. We report here the isolation of a Pc gene encoding a receptor protein that binds both fibronectin and laminin in vitro. A cDNA clone encoding the Pc ECM receptor was isolated from a Pc cDNA library and identified on the basis of sequence homology to the human colon carcinoma laminin receptor. Southern blot analysis of Pc genomic DNA confirmed that the cDNA was of Pc origin. Northern blot analysis of Pc total RNA showed a predominant mRNA of approximately 1400 nucleotides that hybridized to the ECM receptor gene. The ECM receptor predicted from the cDNA sequence is 295 amino acid residues long, with a molecular mass of 32.8 kDa. The C-terminal third of the polypeptide is highly negatively charged, whereas the N-terminal two-thirds contains hydrophobic segments that may play a role in membrane association. Sequence analysis and alignment of the N terminus with the laminin receptor cDNA sequence of human colon carcinoma support the conclusion that the Pc ECM receptor cDNA clone is a full-length clone. A Western blot of the overexpressed ECM receptor protein bound both laminin and fibronectin in vitro. Antibodies raised to the overexpressed receptor protein interacted with a 33-kDa protein in total Pc cell lysates. These findings raise the possibility that the Pc ECM receptor protein may mediate the organism's attachment to type I pneumocytes and, thus, may play a crucial role in Pc pathogenesis.