Binds phosphatidylinositol 4,5-bisphosphate (PIP2). May play a role in the organization of nuclear PIP2, cell division and cell survival (PubMed:15961997). Monomer and homodimer (PubMed:11152476, PubMed:23300061). Interacts with SDCBP (PubMed:11152476). Interacts with TM4SF1 (PubMed:11102519). Associates with intracellular membranes and enriched in the apical region of the cell and in intracellular compartments (PubMed:11102519). Colocalizes with TM4SF1 in the apical region of the cell (PubMed:11102519). Predominantly targeted to nuclear PIP2 pools. Shuttles between several subcellular compartments (PubMed:15961997). PIP2 plays an important role in the distribution of SDCBP2 (PubMed:23300061). Preferentially expressed in cells of the digestive tract (PubMed:11102519). Low expression in skeletal muscle and kidney (PubMed:11102519). Detected in differentiated keratinocytes of normal and malignant epithelium (PubMed:22623796). In healthy skin, expression is localized in suprabasal epidermal layers (PubMed:22623796). Down-regulated by HPV8 E6 papillomavirus (HPV) oncoprotein (at protein level). Binds phosphatidylinositol 4,5-bisphosphate (PIP2) via its two PDZ domains. These domains target SDCBP2 to the plasma membranes and nucleoli, two PIP2-rich regions. The nuclear speckles location of SDCBP2 is under debate. One study shows that in paraformaldehyde fixed cells, SDCBP2 is highly enriched in nuclear speckles (PubMed:15961997). The same authors investigate subcellular location in living cells and fail to detect SDCBP2 in nuclear speckles, and propose that enrichment in nuclear speckles is fixation-dependent (PubMed:23300061).