CBX4 Antibody [F18M1] | Primary Antibodies

Application: Reactivity: Human, Mouse

Lane 1: 22RV1, Lane 2: CAKI-1, Lane 3: HDLM2, Lane 4: NTERA-2

Usage Information

Dilution
WB1:1000 IP1:100 IF1:200 CHIP1:50

Application
WB, IP, IF, ChIP

Reactivity
Human, Mouse

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW
78 kDa

Positive Control	NCCIT cells; MCF7 cells; Caki-1 cells; 293T cells
Negative Control	HDLM2 cells; NTERA-2 cells

Datasheet & SDS

Biological Description

Specificity
CBX4 Antibody [F18M1] detects endogenous levels of total CBX4 protein.

Clone
F18M1

Synonym(s)
E3 SUMO-protein ligase CBX4; Chromobox protein homolog 4; Polycomb 2 homolog (Pc2; hPc2 1); CBX4

Background
CBX4 (Chromobox protein homolog 4) is a core component of the canonical Polycomb Repressive Complex 1 (PRC1) and a unique SUMO E3 ligase that enforces epigenetic gene silencing by recognizing H3K27me3 and modifying non-histone targets. This nuclear protein contains an N-terminal chromodomain for binding trimethylated H3K27, two SUMO-interacting motifs required for its E3 ligase function, a C-terminal chromobox domain for PRC1 assembly, and large intrinsically disordered regions that enable phase separation and diverse protein interactions. CBX4 recruits PRC1 to catalyze histone H2A Lys119 monoubiquitination, repressing developmental and cell cycle genes, while also SUMOylating substrates such as HIF-1α (promoting tumor angiogenesis), BMI1 (facilitating DNA damage repair), and other effectors involved in epithelial-mesenchymal transition, senescence, metabolism, and inflammation. Upregulation of CBX4 drives tumor progression in hepatocellular carcinoma, lung adenocarcinoma, and clear cell renal cell carcinoma via Wnt/β-catenin signaling and cell proliferation, but can also act as a tumor suppressor in colorectal cancer by repressing RUNX2.

Background

CBX4 (Chromobox protein homolog 4) is a core component of the canonical Polycomb Repressive Complex 1 (PRC1) and a unique SUMO E3 ligase that enforces epigenetic gene silencing by recognizing H3K27me3 and modifying non-histone targets. This nuclear protein contains an N-terminal chromodomain for binding trimethylated H3K27, two SUMO-interacting motifs required for its E3 ligase function, a C-terminal chromobox domain for PRC1 assembly, and large intrinsically disordered regions that enable phase separation and diverse protein interactions. CBX4 recruits PRC1 to catalyze histone H2A Lys119 monoubiquitination, repressing developmental and cell cycle genes, while also SUMOylating substrates such as HIF-1α (promoting tumor angiogenesis), BMI1 (facilitating DNA damage repair), and other effectors involved in epithelial-mesenchymal transition, senescence, metabolism, and inflammation. Upregulation of CBX4 drives tumor progression in hepatocellular carcinoma, lung adenocarcinoma, and clear cell renal cell carcinoma via Wnt/β-catenin signaling and cell proliferation, but can also act as a tumor suppressor in colorectal cancer by repressing RUNX2.

References
https://pubmed.ncbi.nlm.nih.gov/38816356/ https://pubmed.ncbi.nlm.nih.gov/22402492/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%