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Senior Investigator

Bechara Kachar, M.D.

Laboratory of Cell Biology, NIDCD
Building 50 Room 4249
36 Convent Drive MSC 0000
Bethesda MD 20892-0000
Office: (301) 402-1600

Fax: (301) 402-1765
kacharb@nidcd.nih.gov

Dr. Kachar received his M.D. degree from the University of Sao Paulo, Brazil in 1977. He did postdoctoral research on membrane structure and intercellular junctions with Pedro Pinto da Silva at the NCI and cell structure and motility with Thomas Reese at the NINDS. Dr. Kachar joined the NIDCD in 1986, becoming chief of the Section on Structural Cell Biology in 1995. Dr. Kachar's laboratory uses advanced microscopy imaging in combination with cell biology techniques to study cellular and molecular mechanisms that underlie mechano-transduction in auditory and vestibular sensory organs. His laboratory also studies permeability barriers in auditory and non-auditory epithelial tissues focusing on the molecular basis of tight junction adhesion and permeability.



The Section on Structural Cell Biology uses advanced microscopy imaging in combination with cell biology techniques to study cellular and molecular mechanisms that underlie mechano-transduction in auditory and vestibular sensory organs.

The auditory and vestibular sensory organs are highly structured and miniaturized devices optimized for sensitivity and speed of response. In these sensory organs, the hair cells are the receptors containing the key mechanoelectrical transduction elements that convert mechanical stimuli into electrical signals. These transduction elements rely on energy exchanges at rates too rapid to involve enzymatic intermediates and are believed to involve direct interactions in protein assemblies driven solely by mechanical energy.

The two main current projects of the Section are: 1) identification and characterization of proteins involved in the mechanosensory transduction apparatus in auditory and vestibular hair cells; and 2) elucidation of the structural and molecular basis of electromotility, a voltage-dependent force-generating mechanism present in cochlear outer hair cells. This mechanism is thought to be responsible for the extraordinary sensitivity of the mammalian ear. Current research also includes the study of permeability barriers in the inner ear focusing on the molecular basis of permeability of the tight junctions of the organ of Corti and the stria vascularis. These junctions support the voltage and potassium concentration gradients that define the endocochlear potential, a critical condition for mechanoelectrical transduction by the hair cells.

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  • 1) Frolenkov GI Mammano F Kachar B (2003)
  • Regulation of outer hair cell cytoskeletal stiffness by intracellular Ca(2+): underlying mechanism and implications for cochlear mechanics.
  • Cell Calcium , 33 , 185-95
  • 2) Schneider ME Belyantseva IA Azevedo RB Kachar B (2002)
  • Rapid renewal of auditory hair bundles.
  • Nature , 418 , 837-8
  • 3) Belyantseva IA Frolenkov GI Wade JB Mammano F Kachar B (2000)
  • Water permeability of cochlear outer hair cells: characterization and relationship to electromotility.
  • J Neurosci , 20 , 8996-9003
  • 4) Belyantseva IA Adler HJ Curi R Frolenkov GI Kachar B (2000)
  • Expression and localization of prestin and the sugar transporter GLUT-5 during development of electromotility in cochlear outer hair cells.
  • J Neurosci , 20 , RC116
  • 5) Kachar B Parakkal M Kurc M Zhao Y Gillespie PG (2000)
  • High-resolution structure of hair-cell tip links.
  • Proc Natl Acad Sci U S A , 97 , 13336-41
  • 6) Azzam NA Hallenbeck JM Kachar B (2000)
  • Membrane changes during hibernation.
  • Nature , 407 , 317-8
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