Taxonomic distribution of proteins containing RESP18 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing RESP18 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Requirement of regulated endocrine-specific protein-18 for development andexpression of regulated endocrine-specific protein-18 isoform c in mice.

Liang M, Yang JL, Bian MJ, Liu J, Hong XQ, Wang YC, Huang YF, Gu SP, Yu M, Huang F, Fei J
Mol Biol Rep. 2011; 38: 2557-62

Regulated endocrine-specific protein-18 (RESP18) is distributed mainly in theperipheral endocrine and neuroendocrine tissues. The expression of RESP18 proteinis regulated by physiological factors, such as blood glucose or dopaminergicdrugs, but its functions remain unclear. In this study, to explore the biologicalfunctions of RESP18 in vivo, we generated RESP18 heterozygous deficient mice, andfurther found RESP18 was essential for embryonic development. In addition, wecloned a new isoform of mouse RESP18 by reverse transcription-polymerase chainreaction (RT-PCR), and denominated it as RESP18-c. Mouse RESP18-c, by skippingexon4 (43 bp in length), encodes a shorter protein of 120 amino acid residues.The distribution of RESP18-c mRNA is similar with that of RESP18 mRNA in theperipheral tissues and brains of mice.

RESP18, a homolog of the luminal domain IA-2, is found in dense core vesicles in pancreatic islet cells and is induced by high glucose.

Zhang G, Hirai H, Cai T, Miura J, Yu P, Huang H, Schiller MR, Swaim WD, Leapman RD, Notkins AL
J Endocrinol. 2007; 195: 313-21

The regulated endocrine-specific protein, RESP18, first found in the ratpituitary, was thought to be regulated by dopaminergic drugs. Bioinformaticsstudies showed that RESP18 shares sequence homology with the luminal region ofIA-2, a dense core vesicle (DCV) transmembrane protein involved in insulinsecretion. The present study was initiated to examine the genomic structure andsubcellular localization of RESP18 and the effect of glucose on its expression.Human RESP18 was isolated from a pancreas cDNA library and its subcellularlocalization was determined by immunoelectron microscopy. MIN6 cells and mouseislets were used to study the effect of glucose on RESP18 expression.Bioinformatics analysis revealed that RESP18 and IA-2 are tandemly arrangedwithin a 45 kb region on human chromosome 2 and share common intron-exonboundaries. By confocal microscopy, RESP18 was found in alpha, beta and deltacells in the pancreatic islets. Electron microscopy revealed that RESP18 ispresent in the lumen of DCVs. The expression of RESP18 in beta cells is markedly increased following exposure to high glucose and also elevated in the islets ofdiabetic, but not non-diabetic, NOD mice. We conclude that RESP18 is a luminalprotein of DCVs and its expression is regulated by exposure to glucose.