Tectorial membrane—A collagen-based gel?

Abstract

According to traditional thinking, the tectorial membrane (TM) is a gel with a matrix of proteins, but containing no collagen. We recently reported patterns of amino acids and proteins of the TM consistent with the presence of substantial amounts of collagen [I. Thalmann et al., J. Acoust. Soc. Am. Suppl. 1 77, S93 (1985)]. Using two-dimensional polyacrylamide gel electrophoresis with extended alkaline range, we have now found that the predominant protein of the TM of the guinea pig virtually superimposes with purified collagen standards. Moreover, peptide mapping of cyanogen bromide digests (“fingerprinting”) results in a pattern closely resembling that of collagen type II. Further procedures for identification and characterization of this protein (effect of collagenase, immunoblotting, etc.) are in progress. At this stage it is not possible to decide to what extent the amino and neutral sugars present in hydrolysates of the TM are part of the alleged collagen molecule. The cupula ampullaris, a vestibular superstructure thought to be analogous to the TM, exhibits a substantially different chemical profile. The functional significance of the findings will be discussed. [Supported in part by NIH.]

Col11a2 Deletion Reveals the Molecular Basis for Tectorial Membrane Mechanical Anisotropy

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