High impact information on SLC12A4

• Human potassium chloride cotransporter 1 (SLC12A4) promoter is regulated by AP-2 and contains a functional downstream promoter element [1].
• K-Cl cotransport is elevated in sickle erythrocytes, and the KCC1 gene has been proposed as a modifier gene in sickle cell disease [1].
• Functional assays of KCl cotransport activation by osmotic swelling, staurosporine, and N-ethylmaleimide indicate that removal of the N-terminal 117 amino acids from KCC1 produces a dominant-negative loss-of-function phenotype for KCl cotransport in human cervical cancer cells [2].
• Hydropathy analysis of KCC1 indicates structural homology to NKCC, including 12 transmembrane domains, a large extracellular loop with potential N-linked glycosylation sites, and cytoplasmic N- and C-terminal regions [3].
• KCC1 was identified by searching the human expressed sequence tag data base, based on the expectation that it would be distantly related to the Na-K-Cl cotransporter [3].

Biological context of SLC12A4

• Consensus DNA sequences from human, mouse and/or rat were used to design oligonucleotide primers for equine homologues of exons 16, 17 and 20-23 of potassium chloride co-transporter (SLC12A4) and exons 10, 11 and 3, 4, respectively, for two amino acid transporters (SLC7A10 and SLC7A9) [4].
• Equine BAC clones were obtained for SLC12A4 and SLC7A10 and mapped to equine chromosomes ECA3p13 and ECA10p15, respectively, by fluorescence in situ hybridization (FISH) [4].
• We report the cloning, sequence analysis, tissue distribution, and functional expression of the K-Cl cotransport protein, KCC1 [3].
• Transient transfection experiments were subsequently performed to characterize a novel KCC1 promoter [5].
• Normal cells exposed to polyclonal anti-Ctd antibodies against Ctd epitopes within a 77 amino acid sequence (a.a.943-1020) revealed granular membrane and cytoplasmic immunostaining, presumably endogenous KCC1 [6].

Anatomical context of SLC12A4

• In addition, we used the polymerase chain reaction to demonstrate the presence of KCC1-KCC4 mRNA in the osteoblast-like cell line [7].
• As well as confirming the widespread expression of KCC1 and KCC2 throughout the brain, we now show a more restricted expression of KCC3a in the hippocampus, choroid plexus and piriform cortex, as well as KCC4 in the choroid plexus and the suprachiasmatic nucleus of the hypothalamus [8].
• We did not detect any full-length mRNA transcripts of human erythroid-KCC1 in circulating reticulocytes [9].
• KCC1 cDNA was cloned in dog erythroblasts that had differentiated from peripheral mononuclear cells [10].

Associations of SLC12A4 with chemical compounds

• Mutation of the Y1087 congener in KCC1 to aspartate also dramatically inhibited cotransporter activity [11].

Other interactions of SLC12A4

• Of the four KCC genes known to encode the respective proteins and their spliced variants, RT-PCR with both rat and human primers revealed the predicted cDNA fragments of KCC1, KCC3a, KCC3b, and KCC4 but not KCC2 in both HLE-B3 cells and in human lens tissue extracts from cataractous patients [12].
• A few reports indicate that the NO/cGMP/PKG signaling pathway regulates KCC1 and KCC3 mRNA expression in VSMCs at the post-transcriptional level [13].

Analytical, diagnostic and therapeutic context of SLC12A4

• This study investigates the cellular localization of KCC1 by confocal microscopy, activation of K-Cl COT by various non-osmotic and osmotic interventions with net unidirectional K and Rb fluxes at 37( degrees )C, and the effect of Ctd deletion on K-Cl COT regulation [6].

References