The Contribution of SERCA to Taste Perception Figure 5. Mean taste preference ratios of WT and Serca3 KO mice using two-bottle preference tests. Taste responses are expressed as taste/water intake ratios of Serca3 KO (filled squares) and WT (open circles) to (A) sucrose, (B) saccharin, (C) monosodium glutamate (MSG), (D) denatonium, (E) quinine, (F) citric acid, and (G) NaCl. Data are means 6 SEMs (n = 9–10, except n = 5 for KO mice for NaCl tests). Mixed-model ANOVA and post hoc t-tests were performed (*p,0.05). doi:10.1371/journal.pone.0023165.g005 Serca2 is co-expressed with T1R3 To investigate the differential effect of Serca3 gene nullification on the taste responses to bitter substances versus sweet and umami compounds, we reasoned that other functionally related proteins such as another member of the SERCA family might compensate in part for Serca3’s absence in the KO mice. RT-PCR showed that Serca2 is expressed in mouse lingual epithelia bearing CV and foliate taste papillae, but Serca1 is not (data not shown). PLoS ONE | www.plosone.org 5 August 2011 | Volume 6 | Issue 8 | e23165