TMEM106B is an endolysosomal transmembrane protein associated with many brain disorders, such as frontotemporal lobar degeneration, Alzheimer’s disease, and hypomyelinating leukodystrophy. In addition, recent cryo-EM studies have identified amyloid fibrils of carboxyl-terminal TMEM106B in the brains of those with neurodegeneration. However, so far little is known about precise functions of TMEM106B in the endolysosome and how the protein is involved in a great variety of human conditions at molecular levels. In this project, we sought to identify interaction partners of TMEM106B in the mouse brain by using immunoprecitation and liquid chromatography tandem mass spectrometry protein identification procedure.