Disease relevance of Trpv5

• In addition, the expression of ECaC1 was investigated in an animal model for Type 2 diabetes mellitus, the Zucker diabetic fatty (ZDF) rat [1].

High impact information on Trpv5

• Sr(2+) and Ba(2+) but not Mg(2+) also evoked inward currents in CaT2-expressing oocytes [2].
• The high sensitivity of CaT2 to Cd(2+) also provides a potential explanation for Cd(2+)-induced hypercalciuria and resultant renal stone formation [2].
• Cd(2+), however, also potently inhibited CaT2-mediated Ca(2+) uptake with an IC(50) of 5.4 micrometer [2].
• The expression pattern of CaT2 in kidney was similar to that of calbindin D(28K) and the sodium calcium exchanger 1, NCX1, by in situ hybridization of adjacent sections [2].
• Unlike ECaC, CaT2 is kidney-specific in the rat and was not detected in intestine, brain, adrenal gland, heart, skeletal muscle, liver, lung, spleen, thymus, and testis by Northern analysis or reverse transcription polymerase chain reaction [2].

Biological context of Trpv5

• CaT1 shows homology (75% amino acid sequence identity) to the apical calcium channel ECaC recently cloned from vitamin D-responsive cells of rabbit kidney and is structurally related to the capsaicin receptor and the TRP family of ion channels [3].
• ECaC1 co-localized with the Ca2+ binding protein calbindin-D(28K) in the beta-cells [1].

Anatomical context of Trpv5

• Similar to the alkaline earth metal ions, application of Cd(2+) elicited inward current in CaT2-expressing oocytes with a K(m) of 1.3 mm [2].
• Calcium-related proteins include the calcium transporters 1 and 2 (CaT1 and CaT2), plasma membrane Ca2+-ATPase 1b (PMCA1b), and calbindin-D9k and -D28k [4].
• Vitamin D upregulates expression of ECaC1 mRNA in semicircular canal [5].
• Expression of the novel epithelial Ca2+ channel ECaC1 in rat pancreatic islets [1].
• These observations provide evidence for the first time of an ECaC-based Ca2+ transport system in SCCD that could maintain the low Ca2+ concentration in vestibular endolymph [5].

Associations of Trpv5 with chemical compounds

• In conclusion, CaT2 may participate in calcium entry into the cells of the distal convoluted tubule and connecting segment of the nephron, where active reabsorption of calcium takes place via the transcellular route [2].

Regulatory relationships of Trpv5

• Further, vitamin D receptor was also expressed in SCCD and it was found by quantitative RT-PCR that incubation for 24 h with 1,25-dihydroxyvitamin D3 upregulated the expression of ECaC1, calbindin-D9k, and calbindin-D28k [5].

Other interactions of Trpv5

• Furthermore, the mRNAs for CaT2 and calbindin D(28K) were colocalized in the same cells [2].
• ECaC1, insulin, and prohormone convertase 1 (a neuroendocrine endoprotease expressed in secretory granules) showed a similar punctate staining [1].
• Identical staining patterns for ECaC1 and insulin were observed, whereas no co-localization of ECaC1 with glucagon was found [1].

References