Adapter protein involved in invadopodia and podosome formation, extracellular matrix degradation and invasiveness of some cancer cells. Binds matrix metalloproteinases (ADAMs), NADPH oxidases (NOXs) and phosphoinositides. Acts as an organizer protein that allows NOX1- or NOX3-dependent reactive oxygen species (ROS) generation and ROS localization. In association with ADAM12, mediates the neurotoxic effect of amyloid-beta peptide. Interacts (via N-terminus) with CYBA (By similarity). Interacts with ADAM12, ADAM15 and ADAM19. Interacts with NOXO1. Interacts (via SH3 domains) with NOXA1. Interacts with FASLG. Cytoplasmic in normal cells and localizes to podosomes in SRC-transformed cells. Found in several cancer cell lines, particularly invasive breast carcinomas and melanomas. The PX domain is required for podosome localization because of its ability to bind phosphatidylinositol 3-phosphate (PtdIns(3)P) and phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2) and, to a lesser extent, phosphatidylinositol 4-phosphate (PtdIns(4)P), phosphatidylinositol 5-phosphate (PtdIns(5)P), and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). Binds to the third intramolecular SH3 domain (By similarity). The fifth SH3 domain mediates binding with ADAM12, ADAM15 and ADAM19. Tyrosine phosphorylated by SRC. Phosphorylation plays a regulatory role in the protein localization. The intramolecular interaction of the PX domain with the third SH3 domain maintains the protein in the cytoplasm and phosphorylation disrupts this interaction, resulting in the redistribution of the protein from cytoplasm to the perimembrane region. Phosphorylated on serine upon DNA damage, probably by ATM or ATR. Gene prediction based on similarity to mouse ortholog and partial transcript data. Belongs to the SH3PXD2 family. Extended N-terminus.