Enables TPR domain binding activity. Involved in cell-substrate junction organization; positive regulation of cell projection organization; and positive regulation of corticotropin secretion. Located in several cellular components, including cell tip; cytoplasmic vesicle; and perinuclear region of cytoplasm. Is active in presynapse. Orthologous to human RAB8B (RAB8B, member RAS oncogene family). [provided by Alliance of Genome Resources, Apr 2022]