Figure 2: Western blot analysis of CD46 expression pattern in stapes footplate pools with different histopathologies. As controls of CD46 expression and western blot procedure, THP-1, C33A, and HeLa cell lines are characterized by exclusive expression of variant f (THP-1, C33A) and coexpression of variants f and g (HeLa), respectively. Beta-actin was used as the housekeeping control of CD46 coexpression in each stapes footplate pools. At the final level of protein expression, normal, and nonotosclerotic stapes footplates are featured by coexpression of c, d, e, f, and l isoforms. In contrast, histologically otosclerotic stapes footplates express further four novel protein isoforms of CD46 (os1–4). Exact molecular weights of os isoforms were calculated by ProteinCalculator (v3.3) online software (http://www.scripps.edu/~cdputnam/protcalc.html).