Disease relevance of CALB1

• The alpha3 subunit was rarely observed in ganglion cells containing calbindin, calretinin, or parvalbumin [1].
• We also describe the presence of calbindin in RINm5F cells, an insulin-producing tumor cell line derived from a radiation-induced rat insulinoma [2].
• This study was an investigation of the effects of vitamin D deficiency on calbindin-D28K (CaBP28K) and testosterone levels in male chickens [3].
• The expression of calbindin in chicks that are divergently selected for low or high incidence of tibial dyschondroplasia [4].
• Progesterone (single im injection of 1 mg/kg body weight, BW) prolonged the period of egg formation and reduced the rate of Ca2+ transport and the concentration of calbindin mRNA in the ESG [5].

High impact information on CALB1

• On SDS-PAGE stained with silver the intact epithelium is seen to contain a large number of bands, the most prominent of which are calbindin and actin [6].
• Calretinin and calbindin are expressed in different sets of neurons throughout the brain [7].
• We identified proteins that have been described previously as expressed in the inner ear, such as beta-tectorin, calbindin, and type II collagen [8].
• The presence of a specific calcium-binding activity at such high levels suggests an important function for cochlear calbindin (BPP23) in hair cell calcium homeostasis and auditory transduction [9].
• Although the basilar papilla contains both receptor hair cells and supporting cells, immunocytochemical studies by others have localized calbindin-like immunoreactivity to the hair cells in the rat auditory receptor epithelium [9].

Biological context of CALB1

• Comparative immunolocalization of the plasma membrane calcium pump and calbindin D28K in chicken retina during embryonic development [10].
• Calretinin is a member of the EF-hand calcium-binding protein family, with a high similarity with calbindin D28k [11].
• Calbindin D28k was purified similarly from bacteria using an expression plasmid provided by W [11].
• The seco-steroid hormone 1,25-dihydroxyvitamin D3 is known to induce the expression of a calcium binding protein termed calbindin-D28K in a variety of target tissues [12].
• Molecular structure of the chicken vitamin D-induced calbindin-D28K gene reveals eleven exons, six Ca2+-binding domains, and numerous promoter regulatory elements [12].

Anatomical context of CALB1

• These results reveal a developmentally regulated expression of GluR2/3 proteins, including their splice variants, and of CB and PV in Purkinje cells [13].
• Of note, the corticoid dorsolateral area (sometimes referred as caudolateral part of the parahippocampal area) contained CB immunoreactivity patches coinciding with Nissl-stained cell aggregates, partially resembling the patches described in the mammalian entorhinal cortex [14].
• We have used immunolabeling against calbindin, neuropeptide Y, and DARPP-32 (dopamine- and adenosine-related phosphoprotein, 32 kDa) for the selective marking of putative accumbens subdivisions and have followed the anterograde transport of biotinylated dextran amine injected to the nucleus tractus solitarii region of 7-day-old domestic chicks [15].
• Prenatal acoustic stimulation influences neuronal size and the expression of calcium-binding proteins (calbindin D-28K and parvalbumin) in chick hippocampus [16].
• Calbindin D28k, a highly conserved protein with Ca2+-sensing and Ca2+-buffering capabilities, is abundant in brain and sensory neurons [17].

Associations of CALB1 with chemical compounds

• In biochemical studies, isolation of intestinal microtubules or tubulin by three distinct procedures revealed increasing levels of associated calbindin-D28K as a function of time after 1,25-(OH)2D3 repletion of vitamin D-deficient chicks [18].
• In vitamin D3-treated or 1,25-(OH)2D3-treated chicks, in the absence of Ca2+ transport, immunofluorescence microscopy of intestinal tissue fixed at 25 C indicated a colocalization of calbindin-D28K and tubulin along epithelial cell brush border and basal-lateral membranes [18].
• An immunocytochemical study of calbindin-D28K in laminae I and II of the dorsal horn and spinal ganglia in the chicken with special reference to the relation to substance P-containing primary afferent neurons [19].
• We have examined the effects of the transcriptional inhibitor alpha-amanitin and the translational inhibitor cycloheximide on levels of calbindin-D28K (28-kDa calcium binding protein, CaBP) and CaBP-mRNA in the vitamin D-replete chick intestine [20].
• However, Ca2+ titration of the fluorescent Ca2+ chelator Quin 2 in the presence of calbindin-D28K yielded a least squares fit optimal for 5.7 +/- 0.8 Ca2(+)-binding sites with macroscopic dissociation constants around 10(-8) M [21].

Physical interactions of CALB1

• Calbindin-D28K is a 1 alpha,25-dihydroxyvitamin D3-dependent protein that belongs to the superfamily of high affinity calcium-binding proteins which includes parvalbumin, calmodulin, and troponin C. All of these proteins bind Ca2+ ligands by an alpha-helix-loop-alpha-helix domain that is termed an EF-hand [21].

Regulatory relationships of CALB1

• It was found that analogs known to bind effectively to the nuclear receptor in vitro could achieve a significant occupancy of the VDR in vivo and stimulated calbindin-D28K messenger RNA and protein synthesis [22].

Other interactions of CALB1

• Expression of GluR2/3 proteins, CB, PV, and the mRNAs coding for GluR2 and GluR3 splice variants all revealed a differential expression during development in chick Purkinje cells [13].
• Calretinin immunoreactivity presented a peak (both in number of cells and in intensity) at E15 and fell dramatically after E20 while calbindin immunoreactivity was restricted to the Purkinje cells and increased with the development of these cells [23].
• The chicken LSO complex was characterized chemoarchitectonically from embryonic to posthatching stages, by using immunohistochemistry for calbindin, tyrosine hydroxylase, NKX2.1, and BEN proteins and in situ hybridization for Nkx2.1, Nkx2.2, Nkx6.1, Shh, and Dlx5 mRNA [24].
• In the mallard, nerve fibres were rarely calbindin positive while definitively positive for VIP [25].
• Northern gel analysis revealed that three species of calbindin-D28K mRNA (2.0, 2.6 and 3.1 kb) were present a priori in the vitamin D-deficient chick brain and that administration of pharmacological doses (6.5 nmol/animal) of 1,25(OH)2D3 failed to influence their relative abundance [26].

Analytical, diagnostic and therapeutic context of CALB1

• In the present study the as yet unexamined relationship among Ca2+ transport, calbindin-D28K, and microtubules was studied by immunofluorescence microscopy [18].
• Electron microscopy with immunogold labeling revealed intestinal epithelial calbindin-D28K to be localized inside of small vesicles and lysosome-like structures, with sparse cytoplasmic labeling [18].
• Sequence analysis identifies six EF-hand calcium-binding domains and reveals 42% and 37% homology to chicken calretinin and calbindin D-28k, respectively [27].
• Immunoblotting and immunoprecipitation experiments with this antiserum indicate that BPP23 is a calcium-binding protein very similar, if not identical, to avian calbindin, the 28-kDa vitamin D-dependent calcium-binding protein [9].
• It was of interest to quantitate the Ca2(+)-binding ability of chick intestinal calbindin-D28K utilizing several different Ca2+ titration methods that cover a range of macroscopic binding constants for weak or strong Ca2+ sites [21].

References