A cell-cell contact zone that consists of membrane invaginations extending from either cell, which contain tight-, gap-, and adherens junctions. Peg and socket contacts form between endothelial cells and pericytes, and between lens fiber cells. [ http://www.neurolex.org/wiki/sao1943947957 http://www.ncbi.nlm.nih.gov/pubmed/12883993 http://www.ncbi.nlm.nih.gov/pubmed/17591898 GOC:tfm http://www.ncbi.nlm.nih.gov/pubmed/16166562 ]