Transmembrane protein required for proper cognitive functions. Involved in the development of dentate gyrus (DG) neuron circuitry, is necessary for AMPA receptors surface expression and proper excitatory postsynaptic currents of DG granule neurons. Regulates the organization and stability of the microtubule network of sensory neurons to allow axonal transport. Through the interaction with DST, mediates the docking of the dynein/dynactin motor complex to vesicle cargos for retrograde axonal transport. In hippocampal neurons, required for BDNF-dependent dendrite outgrowth. Cooperates with SH3GL2 and recruits the WAVE1 complex to facilitate actin-dependent BDNF:NTRK2 early endocytic trafficking and mediate signaling from early endosomes. Interacts with DST (isoform 1). Interacts with SH3GL2. Interacts (via N-terminus) with CYFIP1 and CYFIP2; the interactions associate TMEM108 with the WAVE1 complex. Glycosylated.