CTSK and osteoporosis: Furthermore, we labelled BMM (red arrow) or OC (yellow line) with integrin alpha-M (CD11b) or CTSK, respectively, and found ULK1 downregulation in BMM from ovariectomized mice with osteoporosis compared to those from sham-operated control mice, and mature OC also had less ULK1 expression (Figures 1(g)–1(j)).