Ragulator complex protein LAMTOR2, also known as Endosomal adaptor protein p14, Late endosomal/lysosomal Mp1-interacting protein, Late endosomal/lysosomal adaptor and MAPK and MTOR activator 2, Mitogen-activated protein-binding protein-interacting protein, Roadblock domain-containing protein 3, LAMTOR2, MAPBPIP, and ROBLD3, is a protein which belongs to the GAMAD family. LAMTOR2 / ROBLD3 is a regulator of the TOR pathway, a signaling cascade that promotes cell growth in response to growth factors, energy levels, and amino acids. As part of the Ragulator complex, LAMTOR2 / ROBLD3 recruits the Rag GTPases and the mTORC1 complex to lysosomes, a key step in the activation of the TOR signaling cascade by amino acids. LAMTOR2 / ROBLD3 is an adapter protein that enhances the efficiency of the MAP kinase cascade facilitating the activation of MAPK2. Defects in LAMTOR2 are the cause of immunodeficiency due to defects in MAPBP-interacting protein (ID-MAPBPIP). This form of primary immunodeficiency syndrome includes congenital neutropenia, partial albinism, short stature, and B-cell and cytotoxic T-cell deficiency.