PSMG1/PAC1 Antibody

• 产品编号：CST-13378S      品牌：CST       原厂货号：13378S
• 产品分类：抗体 > 一抗 > 蛋白特异性一抗
• 应用分类：

描述：

PSMG1/PAC1 抗体识别人、猴细胞终内源性的PSMG1/PAC1总蛋白。此抗体不与小鼠、大鼠PSMG1 (PAC1)发生交叉反应。此抗体不与PSMG2 (PAC2)蛋白发生交叉反应。多克隆抗体通过合成与人PSMG1 (PAC1)蛋白氨基末端的邻近氨基酸残基序列一致的肽段，免疫动物产生。26S蛋白酶体是一种高丰度，大小约2 MDa的复合物，它具有泛素蛋白酶体途径的蛋白水解臂。它主要由两种亚型复合物组成，19S调节颗粒(RP)和20S催化核心颗粒(CP)，在许多情况下RPs会覆盖CP的任一末端。CP由包含催化位点的2种堆积β-环组成，每一种β-环由7种亚基组成(β_1-7)，且两侧包含两个分别由七个亚基构成的α环 (α_1-7).。因此，20S CP 的结构为α_1-7β_1-7β_1-7α_1-7。RP包括了一个底部和一个盖子。部分底部由ATPases的六角环组成，功能为打开底物蛋白和打开α-亚基交错的N-末端片段的闸门，从而使得未折叠的底物进入催化部位。盖子主要起特异性识别泛素信号的作用(1)。除了19S帽子之外，其他的蛋白和复合物，例如蛋白酶体活化因子28 (PA28/11S)，与20S的筒状末端结合，从而促进闸门的开放和激活。此外，蛋白酶体相关的DUBs和E3s能够改变底物嵌合的多泛素链，这可能调节了它们对降解的敏感性(2)。蛋白酶体组装伴侣蛋白1(PSMG1 PAC1)是一个进化保守,广泛表达的伴侣蛋白,促进真核蛋白酶体20S CP的α环状的特有生物合成(3、4)。PSMG1(PAC1)与PSMG2 (PAC2)形成异源复合体发挥作用，并最早被鉴定为蛋白酶体亚基结合蛋白(4)。完整PSMG1-PSMG2异源二聚体既促进异源二聚体α环装配和/或稳蛋白定性，并阻止非产α环二聚体的积累(4)。研究表明小鼠Psmg1基因位点的缺失已经证实蛋白酶体伴侣的重要性，其与正常的蛋白酶体成熟和细胞内稳态息息相关。实验已证明缺失Psmg1 / Pac1将会导致胚胎致死(5)。

1. Finley, D. (2009) Annu Rev Biochem 78, 477-513.
2. Lee, M.J. et al. (2011) Mol Cell Proteomics 10, R110.003871.
3. Vidal-Taboada, J.M. et al. (2000) Biochem Biophys Res Commun 272, 156-63.
4. Hirano, Y. et al. (2005) Nature 437, 1381-5.
5. Sasaki, K. et al. (2010) Mol Cell Biol 30, 3864-74.

原厂资料：

Specificity / Sensitivity

PSMG1/PAC1 Antibody recognizes endogenous levels of total PSMG1 (PAC1) protein in human and monkey cells. This antibody weakly cross-reacts with murine and rat PSMG1 (PAC1) protein. This antibody does not cross-react with PSMG2 (PAC2) protein.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues near the amino terminus of human PSMG1 (PAC1) protein. Antibodies are purified by protein A and peptide affinity chromatography.

Background

The 26S proteasome is a highly abundant, ~2 MDa complex that serves as the proteolytic arm of the ubiquitin-proteasome system. It consists largely of two sub-complexes, the 19S regulatory particle (RP) and the 20S catalytic core particle (CP); in many cases two RPs cap either end of a CP. The CP is made of two stacked β-rings that contain the catalytic sites, each of which is made of seven subunits (β_1-7), flanked on either side by two α-rings, which are also made of seven subunits each (α_1-7). Thus, the structure of the 20S CP is α_1-7β_1-7β_1-7α_1-7. The RP includes a base and a lid. The base, in part, is composed of a hexametric ring of ATPases that function to unfold the substrate and open the gate of the interlacing amino-terminal segments of the α-subunits, thus allowing entry of the unfolded substrate into the catalytic chamber. The lid is predominantly involved in specific recognition of the ubiquitin signal (1). In addition to the 19S cap, other proteins and complexes, such as proteasome activator 28 (PA28/11S), bind to the end of the 20S cylinder and activate it by facilitating opening of the gate. Furthermore, proteasome-associated DUBs and E3s can remodel substrate-anchored polyubiquitin chains, which may modulate their susceptibility to degradation (2).Proteasome assembly chaperone 1 (PSMG1, PAC1) is an evolutionarily conserved, ubiquitously expressed chaperone protein that promotes proper biogenesis of the α-ring of the 20S CP of the eukaryotic proteasome (3,4). PSMG1 (PAC1) functions in a heterodimeric complex with PSMG2 (PAC2) and was originally identified as a proteasome subunit binding partner (4). Intact PSMG1-PSMG2 heterodimers both promote heteroheptameric α-ring assembly and/or stability and prevent accumulation of non-productive α-ring dimers (4). Research studies targeting the disruption of the murine Psmg1 locus have substantiated the importance of proteasome chaperones in contributing to normal proteasome maturation and cellular homeostasis by demonstrating that loss of Psmg1/Pac1 function leads to embryonic lethality (5).

1. Finley, D. (2009) Annu Rev Biochem 78, 477-513.
2. Lee, M.J. et al. (2011) Mol Cell Proteomics 10, R110.003871.
3. Vidal-Taboada, J.M. et al. (2000) Biochem Biophys Res Commun 272, 156-63.
4. Hirano, Y. et al. (2005) Nature 437, 1381-5.
5. Sasaki, K. et al. (2010) Mol Cell Biol 30, 3864-74.

注意事项：

Storage: Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM
NaCl, 100 µg/ml BSA and 50% glycerol. Store at –20°C.
Do not aliquot the antibody