ATHEROGENICITY OF POSTPRANDIAL TRIGLYCRIDE-RICH LIPOPROTEINS (PPTGRLP)

两种人单核细胞-巨噬细胞（HMM）膜结合蛋白（MBP）200和235是受体候选物，其结合富含磷脂酰肌醇的脂蛋白中的载脂蛋白（apo）B-48结构域，用于不依赖于apoE的摄取。纯化的还原MBP 200 R的微序列分析表征MBP 200 R的胰蛋白酶肽。 在一维和二维分析中，模拟独特、明确的10-残基序列的合成肽（AEGLMVTGGR）诱导特异性识别MBP 200、235和200 R的抗肽抗体，表明1）配体结合蛋白被测序，2）MBP 200和235在还原后产生MBP 200 R。 这些抗体识别了人血源性、THP-1、U937 MM和内皮细胞（EC）中的MBP，但不能识别人成纤维细胞或中国仓鼠卵巢（CHO）细胞中的MBP。荧光激活细胞分选（FACS）分析根据受体功能的需要将MBP定位在MM表面上。 10个残基，明确的MBP 200衍生的序列是唯一的，在现存的蛋白质数据库中没有匹配。抗肽抗体与网状内皮细胞中具有这种受体活性的MBP结合，但不与缺乏这种受体活性的细胞中的蛋白质结合。 这些研究提供了第一个直接的蛋白质序列和免疫化学数据，一个新的，独特的载脂蛋白B受体的甘油三酯丰富的脂蛋白存在于人单核细胞，巨噬细胞和内皮细胞。抗肽抗体揭示了MBP 200和MBP 235的相互关系：人类单核细胞-巨噬细胞上富含脂蛋白的独特apoB特异性受体。

Two human monocyte-macrophage (HMM) membrane binding proteins, (MBP) 200 and 235, are receptor candidates that bind to the apolipoprotin (apo)B-48 domain in triglyceride-rich lipoproteins for uptake independent of apoE. Microsequence analysis of the purified reduced MBP 200R characterized tryptic peptides of MBP 200R. A synthetic peptide mimicking a unique, unambiguous 10-residue sequence (AEGLMVTGGR) induced antipeptide anti- bodies that specifically recognized MBP 200, 235 and 200R, in 1- and 2- dimensional analyses, indicating 1) the ligand binding protein was sequenced and 2) MBP 200 and 235 yielded MBP 200R upon reduction. These antibodies identified the MBPs in human blood-borne, THP-1, U937 MMs, and endothelial cells (EC) but not in human fibroblasts or Chinese hamster ovary (CHO) cells. Fluorescence activated cell sorting (FACS) analysis located the MBPs on the MM surface as necessary for receptor function. The 10-residue, unambiguous MBP 200-derived sequence is unique, with no matches in extant protein databases. Antipeptide antibodies bind to the MBPs in reticuloendothelial cells that have this receptor activity, but not to proteins in cells that lack this receptor activity. These studies provide the first direct protein sequence and immunochemical data that a new, unique apoB receptor for triblyceride-rich lipoproteins exists in human monocytes, macrophages, and endothelial cells. Antipeptide antibodies reveal interrelationships of MBP 200 and MBP 235: unique apoB-specific receptors for triglyceride-rich lipoproteins on human monocyte-macrophages.