(IMAGE) Kobe University Caption The extracellular domain of SAP-1 extends into the intestinal lumen and its active tyrosine phosphatase domain resides in the cytoplasm. SAP-1 is thought to inhibit the development of colitis by suppressing CEACAM20 functions. Similar to SAP-1, CEACAM20 is localized to the epithelial microvilli. PTP, protein tyrosine phosphatase. Credit 2004- Kobe University. All Rights Reserved. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.