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Abstract #26395 Published in IGR 12-3
Defective membrane expression of the Na+-HCO3− cotransporter NBCe1 is associated with familial migraine
Suzuki M; Van Paesschen W; Stalmans I; Horita S; Yamada H; Bergmans BA; Legius E; Riant F; De Jonghe P; Li YProceedings of the National Academy of Sciences of the United States of America 2010; 107: 15963-15968
Defective membrane expression of the Na+-HCO3− cotransporter NBCe1 is associated with familial migraine Homozygous mutations in SLC4A4, encoding the electrogenic Na+-HCO3− cotransporter NBCe1, have been known to cause proximal renal tubular acidosis (pRTA) and ocular abnormalities. In this study, we report two sisters with pRTA, ocular abnormalities, and hemiplegic migraine. Genetic analysis ruled out pathological mutations in the known genes for familial hemiplegic migraine, but identified a homozygous 65-bp deletion (Δ65bp) in the C terminus of NBCe1, corresponding to the codon change S982NfsX4. Several heterozygous members of this family also presented glaucoma and migraine with or without aura. Despite the normal electrogenic activity in Xenopus oocytes, the Δ65bp mutant showed almost no transport activity due to a predominant cytosolic retention in mammalian cells. Furthermore, coexpression experiments uncovered a dominant negative effect of the mutant through hetero-oligomer formation with wild-type NBCe1. Among other pRTA pedigrees with different NBCe1 mutations, we identified four additional homozygous patients with migraine. The immunohistological and functional analyses of these mutants demonstrate that the near total loss of NBCe1 activity in astrocytes can cause migraine potentially through dysregulation of synaptic pH.
Classification:
9.4.15 Glaucoma in relation to systemic disease (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)
3.6 Cellular biology (Part of: 3 Laboratory methods)