抄録
CBP-15, a small and acidic calcium-binding protein in the organ of Corti of the guinea pig found by Senarita et al (1995), was qualitatively analyzed using the cochleae of the guinea pigs, rats and mice in this study.
Partial amino acid sequence including N-terminal for CBP-15 obtained from the guinea pig cochlea coincided with that of β-type parvalbumin, i.e.oncomodulin (OM), which had never been identified in the inner ear tissue of any other species.
CBP-15 was also found in the organ of Corti of the mice studied. Monoclonal and polyclonal antibodies to rat OM cross-reacted with CBP-15s in the guinea pigs, rats, and mice. Furthermore, this cross-reaction was strongly observed in the outer hair cells in the organ of Corti of the guinea pigs.
Several authors reported that OM was able to stimulate a phosphodiesterase and to accelerate DNA synthesis in calcium-deprived rat liver at a tenfold lower concentration than calmodulin.
These present results strongly suggest that OM plays an important role in the calcium regulation within the outer hair cells of the cochlea.
