PUBLICATION

Parvalbumin 3 is an abundant Ca2+ buffer in hair cells

Authors
Heller, S., Bell, A.M., Denis, C.S., Choe, Y., Hudspeth, A.J.
ID
ZDB-PUB-100505-1
Date
2002
Source
Journal of the Association for Research in Otolaryngology : JARO   3(4): 488-498 (Journal)
Registered Authors
Keywords
afferent synapse, efferent synapse, electrical resonance, mechanoelectrical transduction
MeSH Terms
  • Amino Acid Sequence/genetics
  • Animals
  • Animals, Newborn
  • Buffers
  • Calcium/metabolism*
  • Chickens
  • Cloning, Molecular
  • DNA, Complementary/genetics
  • Embryo, Mammalian/metabolism
  • Embryo, Nonmammalian
  • Female
  • Hair Cells, Auditory/embryology
  • Hair Cells, Auditory/metabolism*
  • Organ of Corti/metabolism
  • Osmolar Concentration
  • Parvalbumins/genetics
  • Parvalbumins/metabolism*
  • Rabbits
  • Rana catesbeiana
  • Saccule and Utricle/metabolism
  • Zebrafish/embryology
PubMed
12072915 Full text @ J. Assoc. Res. Otolaryngol.
Abstract
Ca2+ signaling serves distinct purposes in different parts of a hair cell. The Ca2+ concentration in stereocilia regulates adaptation and, through rapid transduction-channel reclosure, underlies amplification of mechanical signals. In presynaptic active zones, Ca2+ mediates the exocytotic release of afferent neurotransmitter. At efferent synapses, Ca2+ activates the K+ channels that dominate the inhibitory postsynaptic potential. A copious supply of diffusible protein buffer isolates the three signals by restricting the spread of free Ca2+ and limiting the duration of its action. Using cDNA subtraction and a gene expression assay based on in situ hybridization, we detected abundant expression of mRNAs encoding the Ca2+ buffer parvalbumin 3 in bullfrog saccular and chicken cochlear hair cells. We cloned cDNAs encoding this protein from the corresponding inner-ear libraries and raised antisera against recombinant bullfrog parvalbumin 3. Immunohistochemical labeling indicated that parvalbumin 3 is a prominent Ca2+-binding protein in the compact, cylindrical hair cells of the bullfrog's sacculus, and occurs as well in the narrow, peanut-shaped hair cells of that organ. Using quantitative Western blot analysis, we ascertained that the concentration of parvalbumin 3 in saccular hair cells is approximately 3 mM. Parvalbumin 3 is therefore a significant mobile Ca2+ buffer, and perhaps the dominant buffer, in many types of hair cell. Moreover, parvalbumin 3 provides an early marker for developing hair cells in the frog, chicken, and zebrafish.
Genes / Markers
Figures
Show all Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping