p23_like domain found in proteins similar to Calcyclin-Binding Protein(CacyBP)/Siah-1-interacting protein (SIP). CacyBP/SIP interacts with S100A6 (calcyclin), with some other members of the S100 family, with tubulin, and with Siah-1 and Skp-1. The latter two are components of the ubiquitin ligase that regulates beta-catenin degradation. The beta-catenin gene is an oncogene participating in tumorigenesis in many different cancers. Overexpression of CacyBP/SIP, in part through its effect on the expression of beta-catenin, inhibits the proliferation, tumorigenicity, and invasion of gastric cancer cells. CacyBP/SIP is abundant in neurons and neuroblastoma NB2a cells. An extensive re-organization of microtubules accompanies the differentiation of NB2a cells. CacyBP/SIP may contribute to NB2a cell differentiation through binding to and increasing the oligomerization of tubulin. CacyBP/SIP is also implicated in differentiation of erythroid cells, rat neonatal cardiomyocytes, in mouse endometrial events, and in thymocyte development.