A vitellogenic-like carboxypeptidase expressed by human macrophages is localized in endoplasmic reticulum and membrane ruffles
A vitellogenic-like carboxypeptidase expressed by human macrophages is localized in endoplasmic reticulum and membrane ruffles
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DOI：
10.1111/j.0959-9673.2006.00450.x
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发表时间：
2006-02-01
影响因子：
3
通讯作者：
Gordon, S
中科院分区：
文献类型：
--
作者：
Harris, J;Schwinn, N;Gordon, S
卵黄生成样羧肽酶（Carboxypeptidase，vitellogenic-like，CPVL）是一种功能未知的丝氨酸羧肽酶，最早发现于人类巨噬细胞。最初的研究表明，CPVL在很大程度上限于单核细胞谱系，尽管它也可以由免疫系统外的细胞表达。在这里，我们使用一种新的单克隆抗体来表征CPVL在人巨噬细胞中的特性和定位，以阐明蛋白酶的可能功能。在单核细胞（MO）成熟为巨噬细胞的过程中，CPVL上调，尽管该蛋白质在两者中均可见。在原代巨噬细胞中，CPVL被高甘露糖残基糖基化，并与内质网标记物共定位，而在MO中，它更分散，与内质网的关联不太明显。CPVL在板状伪足和膜皱褶中高度表达，其还浓缩分泌途径的标志物（MIP-1 α和肿瘤坏死因子-α）和主要组织相容性复合体（MHC）I类和II类分子。CPVL可在早期乳胶珠和白色念珠菌吞噬体上看到，但不像MHC I/II类那样保留在成熟的吞噬体中。CPVL具有混合的胞质和膜相关定位，但在外质膜上检测不到。我们建议，CPVL可能参与抗原加工，分泌途径和/或在肌动蛋白重塑和板状伪足形成。
Carboxypeptidase, vitellogenic-like (CPVL) is a serine carboxypeptidase of unknown function that was first characterized in human macrophages. Initial studies suggested that CPVL is largely restricted to the monocytic lineage, although it may also be expressed by cells outside the immune system. Here, we use a new monoclonal antibody to characterize the properties and localization of CPVL in human macrophages to elucidate a possible function for the protease. CPVL is up-regulated during the maturation of monocytes (MO) to macrophages, although the protein can be seen in both. In primary macrophages, CPVL is glycosylated with high mannose residues and colocalizes with markers for endoplasmic reticulum, while in MO it is more disperse and less clearly associated with endoplasmic reticulum. CPVL is highly expressed in lamellipodia and membrane ruffles, which also concentrate markers of the secretory pathway (MIP-1 alpha and tumour necrosis factor-alpha) and major histocompatibility complex (MHC) class I and II molecules. CPVL can be seen on early latex bead and Candida albicans phagosomes, but it is not retained in the maturing phagosome, unlike MHC class I/II. CPVL has a mixed cytosolic and membrane-associated localization but is not detectable on the outer plasma membrane. We propose that CPVL may be involved in antigen processing, the secretory pathway and/or in actin remodelling and lamellipodium formation.