RAB3D and synovial sarcoma: Since downregulation of Rab3D and upregulation of CTSS expression is associated with increased CTSS activity in stimulated tears of the male NOD mouse model of SS [17], to determine whether IFN-γ exposure could promote comparable changes in regulated CTSS secretion, we assayed its stimulated secretion in parallel with the abundant tear protein, β-hexosaminidase.