(A) Representative immunoblot assessing mTOR signaling mediators in LSK and MP cells. (B) Representative immunoblot of mTOR signaling mediators in hematopoietic stem and myeloid progenitor cell populations present within LSK (HSC, MPPa, MPPb) and MP (CMP, GMP and MEP) populations. (C) Quantitation of total mTOR and phosphorylated p70S6K was performed by normalizing to GAPDH and total S6K expression, respectively (n = 3), in hematopoietic stem and myeloid progenitor cell populations. (D) Poly/subpoly RNA ratios for WT LSK and MP cells following ex vivo treatment with Torin 1 or DMSO for 2 hours. (E) qPCR for mTOR mRNA in LSK and MP cells (n=4). (F) Immunoblot for mTOR after in vivo bortezomib treatment of WT mice. Equal numbers (100,000 cells) of LSK and MP cells were analyzed. (G) Immunoblots and quantitation of mTOR in LSK and MP subpopulations (CMP, GMP, MEP) from WT and c-Cbl−/− mice. Representative immunoblots shown (n=3). (H) Representative immunoprecipitation experiment of mTOR in the mouse hematopoietic progenitor cell line, HPC-7 (n=3). (I) Immunoblots for ubiquitin following immunoprecipitation with mTOR or control antibodies from HPC-7 lysates.