Kitamura K, Matsuda A, Motoya S, Takeda A
Department of Pathology, Roger Williams Medical Center-Brown University, Providence, RI 02908, USA.
Eur J Immunol. 1997 Feb;27(2):383-8. doi: 10.1002/eji.1830270207.
CD45-AP is a recently identified CD45-associated protein. The two proteins interact specifically through their respective transmembrane segments. Northern hybridization analysis of CD45+ T lymphocytes and their CD45- variants demonstrated that the production of CD45-AP and CD45 mRNA is regulated independently. On the other hand, Western blotting analysis indicated that the CD45-AP protein has a shorter half-life in the absence of CD45 in three out of four variants. Similar analysis of various types of leukocytes demonstrated that CD45-AP is expressed in T, B, and pre-B cells, but not in plasma cells or cells of the monocyte/macrophage lineage. Two forms of CD45-AP mRNA exist in all types of CD45-AP-expressing lymphocytes analyzed. One form corresponds to the previously reported CD45-AP cDNA and the other form encodes an additional 12 amino acids at the N terminus. The two CD45-AP proteins are identical in their capacity for specific binding to CD45, but employ different mechanisms for endoplasmic reticulum membrane translocation.
CD45-AP是一种最近发现的与CD45相关的蛋白质。这两种蛋白质通过它们各自的跨膜区段特异性相互作用。对CD45+ T淋巴细胞及其CD45-变体进行的Northern杂交分析表明，CD45-AP和CD45 mRNA的产生是独立调节的。另一方面，蛋白质印迹分析表明，在四种变体中的三种变体中，CD45-AP蛋白在没有CD45的情况下半衰期较短。对各种类型白细胞的类似分析表明，CD45-AP在T细胞、B细胞和前B细胞中表达，但在浆细胞或单核细胞/巨噬细胞系细胞中不表达。在所分析的所有表达CD45-AP的淋巴细胞类型中存在两种形式的CD45-AP mRNA。一种形式对应于先前报道的CD45-AP cDNA，另一种形式在N末端编码另外12个氨基酸。这两种CD45-AP蛋白在与CD45特异性结合的能力上是相同的，但采用不同的机制进行内质网膜易位。
