Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022716 (Menkes)
 1,057 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported that copper efflux from C6 rat glioma cells was blocked by a brief exposure to sulfhydryl reagents p-chloromercuribenzoate (PCMB) and iodoacetamide as well as dicyclohexylcarbodiimide, suggesting the possible involvement of a Cu-transporting ATPase in the efflux mechanism. In this report, we show that copper efflux from PC12 cells, a neuron-like cell line established from rat adrenal pheochromocytoma, is also inhibited by PCMB exposure. Furthermore, we show that both C6 and PC12 cells express a homolog of the Menkes gene (MNK) as detected by RT-PCR with primers designed from a mouse cDNA and confirmed by sequence analysis of the amplified product. An expected 760-bp fragment representing the transduction and phosphorylation domains and a 925-bp fragment encoding the heavy metal-binding domain of Atp7a were amplified from a RNA extract of C6 and PC12 cells. Sequence data revealed that 690 bp of the 760-bp fragment from C6 cells were an identical match to a similar fragment from PC12 cells. Both fragments encoded a 229 amino-acid polypeptide that had a 98.7% sequence homology to mouse Atp7a. In addition, 880 bp from the 925-bp fragment of the two cell lines were identical and encoded a 293 amino-acid polypeptide with 94.5% sequence homology to mouse Atp7a. These data establish that a Menkes-type Cu-transporting ATPase is expressed in rat C6 and PC12 cells and strongly support the hypothesis that both neurons and glia are involved in maintaining Cu homeostasis in the central nervous system.
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PMID:A Menkes P-type ATPase involved in copper homeostasis in the central nervous system of the rat. 937 50

Previously, we showed that the transport of Cu by PC12 pheochromocytoma cells and C6 glioma cells correlated with the expression of a Cu-transporting ATPase (Atp7a) that has been linked to Menkes disease. Here, we show that cerebrovascular endothelial (CVE) cells that comprise the blood-brain barrier (BBB) also express the gene for the Cu-ATPase. By using reverse transcription-polymerase chain reaction (RT-PCR) and primers designed from mouse Atp7a cDNA, we amplified a 925-bp and a 760-bp cDNA fragment from two extreme regions of Atp7a mRNA from murine CVE cells; 777 bp of the 925-bp fragment and 677 bp of the 760-bp fragment had a 99.7 and 100% sequence homology, respectively, with mouse Atp7a cDNA. The 777-bp sequences covered the heavy metal binding (Hmb) domain and the 677-bp fragment coded for residues at the -COOH terminus of Atp7a. A functional analysis showed that Cu efflux was blocked by the sulfhydryl reagent p-chloromercuribenzoate (p-CMB), a potential inhibitor of Atp7a function. This study provides strong evidence that a Cu-ATPase in the BBB controls the penetration of Cu into the brain and that lesions to the Cu-ATPase in CVE cells are a primary cause of low brain Cu levels in Menkes disease.
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PMID:Copper efflux from murine microvascular cells requires expression of the menkes disease Cu-ATPase. 968 44