ROBLD3 is a member of the GAMAD family. ROBLD3 is an adapter protein which enhances the efficiency of the MAP kinase cascade and facilitates the activation of MAPK2. ROBLD3 compels the recruitment of MP1 to late endosomes where they form a very stable heterodimeric complex required for ERK activation on endosomes. In humans， a mutation in the ROBLD3 gene has been associated with a primary immunodeficiency syndrome， and suggests a role for the ROBLD3 protein in endosomal biogenesis.
