Disease relevance of Chgb

• In contrast, the level of CgB mRNA, that was not changed by ovariectomy, was increased after estrogen treatment, probably secondary to prolactin cell hyperplasia [1].
• Ewing's sarcomas and PNETs, unlike neuroblastomas, were negative for CgA and CgB [2].
• Here we generated transgenic mice expressing CgB under the control of the human cytomegalovirus promoter [3].
• In GH3 cells various prohormone convertases were overexpressed together with the substrate chromogranin B by use of a vaccinia virus infection system [4].

Psychiatry related information on Chgb

• Peptides found to be elevated by food deprivation but not exercise included a number of fragments of proenkephalin, prothyrotropin-releasing hormone, secretogranin II, chromogranin B, and pro-SAAS [5].

High impact information on Chgb

• Chromogranin B (CgB, secretogranin I) is a secretory granule matrix protein expressed in a wide variety of endocrine cells and neurons [3].
• Upon subcellular fractionation of the exocrine pancreas, the distribution of CgB in the various fractions was indistinguishable from that of amylase, an endogenous constituent of zymogen granules [3].
• Immunogold electron microscopy of pancreatic acinar cells showed co-localization of CgB with zymogens in Golgi cisternae, condensing vacuoles/immature granules and mature zymogen granules; the ratio of immunoreactivity of CgB to zymogens being highest in condensing vacuoles/immature granules [3].
• Two distinct chromogranin B-derived peptides result from cleavage at Trp-Trp bonds, a site not typically associated with neuropeptide processing [6].
• The expression of phenylethanolamine N-methyl transferase and chromogranin B mRNA was similar in TH-null and wild-type mice [7].

Biological context of Chgb

• Three exons also displayed both length and sequence homology to exons in another member of the chromogranin/secretogranin family, chromogranin B, suggesting an evolutionary relationship [8].
• Chromogranin B-induced secretory granule biogenesis: comparison with the similar role of chromogranin A [9].
• Significant QTLs derived from SCG/Kj on chromosomes 1, 2, 7, and 13 were designated Scg-1 to Scg-5, respectively, and those derived from B(6) on chromosomes 4, 6, 17, and 10 were designated Sxb-1 to Sxb-4, respectively [10].
• In these clones, investigated as such or after transfection with chromogranin A antisense sequences, the ratio between chromogranin A and its secretory protein mate, chromogranin B, was not constant but highly and apparently randomly variable [11].
• Their number/cell appears independent of chromogranin A and their composition does not appear to be constant; in particular, they exhibit considerable, and so far unexplained variability in the chromogranin A/chromogranin B ratio [11].

Anatomical context of Chgb

• Recently, secretory granule Ca(2+) storage protein chromogranin B (CGB) was shown to be present in the nucleoplasm proper in a complex structure that consists of the inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca(2+) channels and the phospholipids [12].
• In contrast, inhibition of CGA expression in PC12 cells by siRNA treatment decreased the IP(3)-induced Ca(2+) releases in the nucleus by 17%, while inhibition of CGB expression decreased the IP(3)-induced Ca(2+) releases in the nucleus by 55% [12].
• Peptides found to increase corresponded to fragments of proenkephalin, prothyrotropin-releasing hormone, provasopressin, proSAAS, secretogranin II, chromogranin B, and peptidyl-glycine-alpha-amidating mono-oxygenase in the hypothalamus [13].
• Chromogranin B-like immunoreactivity in the mouse submandibular salivary gland during postnatal development [14].
• Recently, we have isolated from bovine chromaffin granules and identified two natural peptides possessing antibacterial activity: secretolytin (chromogranin B 614-626) and enkelytin (proenkephalin-A 209-237) [15].

Associations of Chgb with chemical compounds

• Therefore, we investigated here the potential contribution of nuclear CGB on the IP(3)-dependent Ca(2+) mobilization in the nucleus, using both neuroendocrine PC12 and nonneuroendocrine NIH3T3 cells [12].
• Role of nuclear chromogranin B in inositol 1,4,5-trisphosphate-mediated nuclear Ca2+ mobilization [12].
• This gene codes for a protein, referred to as sulfophilin, which consists of a 12-times repeated heptapeptide unit corresponding to the identified tyrosine sulfation site of chromogranin B (secretogranin I), Glu-Glu-Pro-Glu-Tyr-Gly-Glu [16].
• A functional interaction between chromogranin B and the inositol 1,4,5-trisphosphate receptor/Ca2+ channel [17].
• In pulse-chase experiments, significant intracellular storage of secretogranin II and chromogranin B was observed and secretion of retained secretogranin II was stimulated with the calcium ionophore A23187 [18].

Other interactions of Chgb

• Microinjection of IP(3) into the nucleus of CGB-expressing NIH3T3 cells increased the IP(3)-dependent nuclear Ca(2+) mobilization approximately 3-fold, whereas in CGA-expressing cells it remained the same as that of control cells [12].
• PC1 appeared to be by far the most active enzyme and converted chromogranin B to several smaller molecules, including the peptide PE-11 [4].
• Some processing of chromogranin B and formation of free PE-11 were also observed with PC2 and PACE4 [4].
• Northern and immunoblot analyses, in situ hybridization and immunocytochemistry revealed that the exocrine pancreas was the tissue with the highest level of ectopic CgB expression [3].
• Proenkephalin mRNA in both saline- and ACTH-treated CRHR1 null mice were higher than in control animals (215.8% P <0.05, 268.9% P <0.01) whereas expression of neuropeptide Y and chromogranin B did not differ [19].

Analytical, diagnostic and therapeutic context of Chgb

• Variability of the chromogranin A/chromogranin B ratio was seen by confocal immunofluorescence also among the cells of single clones and subclones and among the granules of single cells [11].

References