Mutation R184Q of connexin 26 in hearing loss patients has a dominant-negative effect on connexin 26 and connexin 30.
Hearing impairment is the most common sensory disorder worldwide. In a recent study, the authors have shown that a heterozygous missense mutation, p.R184Q, in the connexin 26 (Cx26) is causally related to hearing loss. However, the functional change in the Cx26R184Q mutant remains unknown. This study compared the intracellular distribution and assembly of mutant Cx26R184Q with that of the wild-type (WT) Cx26 and Cx30WT in tet-on HeLa cells and the effect that the mutant protein had on those cells. Fluorescent localization assay of WT Cx26 showed the typical punctuate pattern of gap junction channel between neighboring expression cells. Conversely, the p.R184Q missense mutation resulted in accumulation of the Cx26 mutant protein in the Golgi apparatus rather than in the cytoplasmic membrane. Cx26R184Q coexpressed with either Cx26WT or Cx30WT showed perinuclear localization by bidirectional tet-on expression system, suggesting the impairment of the ability of both WT proteins to intracellular trafficking and targeting to the plasma membrane. Therefore, we proposed that Cx26R184Q has a dominant-negative effect on the function of WT Cx26 and Cx30.
Su
Ching-Chyuan
CC
Tian-Sheng Memorial Hospital, Taiwan, Republic of China.
Li
Shuan-Yow
SY
Su
Mao-Chang
MC
Chen
Wei-Chi
WC
Yang
Jiann-Jou
JJ
D001483:Base Sequence; D003001:Cloning, Molecular; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers; D005799:Genes, Dominant; D006367:HeLa Cells; D034381:Hearing Loss / Q000235:genetics*; D006801:Humans; D009154:Mutation
D000075302:Connexin 30; D017630:Connexins; D017931:DNA Primers; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; D000072259:Connexin 26