Disease relevance of CBX4

• However, the hPc2 and CBX2/hPc1 proteins colocalize in interphase nuclei of human U-2 OS osteosarcoma cells, suggesting that the proteins are part of a common protein complex [1].
• The c-myb proto-oncogene was amplified in 10% of the pancreatic carcinoma tissues and in the pancreatic cancer cell line PC2 [2].
• These results show for the first time expression of PC2 in human pheochromocytomas which may be involved in the processing of proenkephalin [3].

High impact information on CBX4

• However, Pc2 dramatically enhances CtBP sumoylation [4].
• The polycomb protein Pc2 is a SUMO E3 [4].
• Phosphorylation-Dependent Control of Pc2 SUMO E3 Ligase Activity by Its Substrate Protein HIPK2 [5].
• Granule formation, and the sorting of SgII and PC2 from the trans-Golgi network into ISGs and MSGs, however, is not affected [6].
• Mutation of the CtBP binding site on Pc2 abolishes E3 activity toward CtBP [7].

Biological context of CBX4

• Interference with the expression of a novel human polycomb protein, hPc2, results in cellular transformation and apoptosis [1].
• Our data suggest that hPc2 is a repressor of proto-oncogene activity and that interference with hPc2 function can lead to derepression of proto-oncogene transcription and subsequently to cellular transformation [1].
• Expression of the delta hPc2 protein, but not of the wild-type hPc2 protein, results in cellular transformation of mammalian cell lines as judged by phenotypic changes, altered marker gene expression, and anchorage-independent growth [1].
• Inducible phosphorylation of Pc2 at threonine 495 is required for its ability to increase HIPK2 sumoylation in response to DNA damage, thereby establishing an autoregulatory feedback loop between a SUMO substrate and its cognate E3 ligase [5].
• The PCA of the 1H NMR spectra of the aqueous fractions allowed a clear discrimination between antler samples according to their origins by the first three principal components (PC1, PC2, and PC3), which cumulatively accounted for 93.5% of the variation in all variables [8].

Anatomical context of CBX4

• This concurs with the absence of prohormone convertase 2 (PC2) in the embryo, whereas PC2 is present later in embryonic pancreas [9].
• In both AtT-20 cells and hEK-293 cells, the PAM/PC2 fusion molecule was able to exit the endoplasmic reticulum more rapidly than PC2 [10].
• In this report, the regulatory role of actin dynamics on PC2 channels reconstituted from hST apical membranes was explored [11].
• PC2 could only be detected in normal adrenal glands using the sensitive RT/PCR technique [3].
• It has been previously shown that PMs and synthetic particles (PC10 and PC2) that have similar characteristics to PMs induced depolarizing currents and increases in intracellular calcium ([Ca2+]i) in capsaicin- and acid-sensitive sensory neurons and in TRPV1-expressing HEK 293 cells [12].

Associations of CBX4 with chemical compounds

• Immobilized template assays in which activator-recruited preinitiation complexes were allowed to undergo one cycle of transcription revealed partial disruption of Mediator that resulted in a PC2-like complex being retained in the scaffold [13].
• Aspartate at the oxyanion hole appears to confer k(caf) discrimination between substrates by raising the energy barrier for productive substrate binding: this may have implications for pro-insulin processing by the PC2 protease, which has an aspartate at the equivalent position [14].
• To elucidate the mechanism of this disease, we stably expressed five vasopressin prohormones with a mutation in the neurophysin moiety (NP14G-->R, NP47E-->G, NP47DeltaE, NP57G-->S, and NP65G-->V) in the neuroendocrine cell lines Neuro-2A and PC12/PC2 [15].
• Curiously, the mammalian protease PC2, a Kex2 homolog that is likely to be required for pro-insulin processing, has an aspartate in place of asparagine at the 'oxyanion hole'. RESULTS: We have tested the effect of making substitutions of the conserved oxyanion-hole asparagine (Asn 314) of the Kex2 protease [14].
• Two most effective detection potentials were selected: 780 mV for the GSSG and PC2 and 680 mV for determination of Cys and GSH [16].

Other interactions of CBX4

• The human PcG protein, Pc2, has been shown to recruit the transcriptional corepressor, CtBP, to PcG bodies [4].
• The interactions between Ring1, hPc2, and KyoT2 were confirmed by changing vectors in two-hybrid analysis [17].
• Interactions of KyoT2 with Ring1 and hPc2 suggested that PcG family might be involved in Notch signaling pathway [17].

Analytical, diagnostic and therapeutic context of CBX4

• The actin-binding proteins alpha-actinin and gelsolin, as well as PC2, were observed by Western blot and immunofluorescence analyses in hST vesicles [11].
• Moreover, in situ hybridization and immunohistochemistry confirmed expression of PC2 in human tumoral adrenal medullary tissue [3].
• By Northern blot, PC2 and proenkephalin were expressed in 85% and 90% of the 20 pheochromocytomas studied, respectively [3].
• No significant difference between PC2 values of the MG and control groups was observed (p>0.05) [18].
• For each monitoring period, HR values were recorded at 5 second intervals or less from the ECG, SpO2 and IAC using a SpaceLabs Medical Gateway connected to a SpaceLabs Medical PC2 [19].

References