Is ASBT mRNA distribution across segments concordant with protein distribution? (discordance)

• A. Yes
• B. No
• C. Partially
• D. Not assessed

Answer: (B)

The distribution of ASBT mRNA across intestinal segments does not necessarily match where the protein ends up, because mRNA levels reflect transcriptional activity, while protein localization depends on additional steps after transcription. Translation efficiency, mRNA stability, and post-translational regulation can vary by segment, and the transporter must be properly trafficked to the apical membrane of enterocytes to be functional. In the ileum, ASBT protein is prominently localized to the brush border to mediate bile acid reabsorption, whereas mRNA might be present more broadly but not all segments produce or traffic the protein to the surface. This mismatch between where the transcript is and where the protein actually resides illustrates discordance, making No the best answer.