A helix-breaking mutation in TRPML3 leads to constitutive activity underlying deafness in the varitint-waddler mouse
| Autor: | Michael E. Schnee, Corné J. Kros, Math P. Cuajungco, Anthony J. Ricci, Stefan Heller, Alexander F. J. van Aken, Simone Jörs, Christian Grimm |
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| Rok vydání: | 2007 |
| Předmět: |
Gene isoform
Proline Molecular Sequence Data Mutant TRPM Cation Channels Apoptosis Biology medicine.disease_cause Protein Structure Secondary Cell Line Mice Transient receptor potential channel Transient Receptor Potential Channels Protein structure medicine Animals Amino Acid Sequence Hearing Loss Ion channel Mutation Multidisciplinary Biological Sciences medicine.disease Molecular biology Protein Structure Tertiary medicine.anatomical_structure Amino Acid Substitution Mucolipidosis type IV Hair cell |
| Zdroj: | Proceedings of the National Academy of Sciences. 104:19583-19588 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0709846104 |
| Popis: | Homozygote varitint-waddler ( Va ) mice, expressing a mutant isoform (A419P) of TRPML3 (mucolipin 3), are profoundly deaf and display vestibular and pigmentation deficiencies, sterility, and perinatal lethality. Here we show that the varitint-waddler isoform of TRPML3 carrying an A419P mutation represents a constitutively active cation channel that can also be identified in native varitint-waddler hair cells as a distinct inwardly rectifying current. We hypothesize that the constitutive activation of TRPML3 occurs as a result of a helix-breaking proline substitution in transmembrane-spanning domain 5 (TM5). A proline substitution scan demonstrated that the inner third of TRPML3's TM5 is highly susceptible to proline-based kinks. Proline substitutions in TM5 of other TRP channels revealed that TRPML1, TRPML2, TRPV5, and TRPV6 display a similar susceptibility at comparable positions, whereas other TRP channels were not affected. We conclude that the molecular basis for deafness in the varitint-waddler mouse is the result of hair cell death caused by constitutive TRPML3 activity. To our knowledge, our study provides the first direct mechanistic link of a mutation in a TRP ion channel with mammalian hearing loss. |
| Databáze: | OpenAIRE |
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