a, Exchange rates of amino acids between the indicated cells and their media measured after 48 h treatment with or without 25 mM mannose. Results are presented as peak area per microgram of protein per hour and are representative of one experiment. Shown is the mean of six technical replicates. b, Levels of 13C 16 -palmitate (expressed as peak area per microgram of protein) in U2OS-E1a cells incubated with 50 µM 13C 16 -palmitate, conjugated with 10% fatty-acid-free BSA, for 24 h in the presence or absence of 25 mM mannose in the culture medium (DMEM). n = 2 independent experiments (each involving six technical replicates). Data are mean ± s.e.m. c, d, Levels of 13C 3 -serine (c) and 13C 2 -glycine (d) (expressed as peak area per micrograms of protein) in U2OS-E1a cells incubated with 25 mM 13C 6 -glucose for the indicated time in the presence or absence of 25 mM mannose in the culture medium (DMEM). n = 3 independent experiments. e, f, Distribution of isotopologues of intracellular serine (e) and glycine (f) in U2OS-E1a cells incubated with 25 mM 13C 6 -glucose for 24 h in the presence (mannose) or absence (ctr) of 25 mM mannose in the culture medium (DMEM). n = 3 independent experiments. g, Mannose has no effect on the unfolded protein response. U2OS-E1a cells were treated with 25 mM mannose for 16 and 24 h. 2-Deoxy-d-glucose (2DG) and tunicamycin (TM) serve as positive controls. Induction of Bip (also known as GRP78) is a read-out of endoplasmic reticulum stress. The data are representative of three independent experiments. h, Proteasome activity is not affected by mannose. Mannose-sensitive U2OS-E1a cells were incubated in either DMEM or DMEM containing 25 mM mannose before measurement of proteasome activities. Cells were also treated with10 μM MG132 as a control for proteasome activity. n = 3 independent experiments. i, j, U2OS-E1a cells (i) or U2OS-E1a (U2OS) cells overexpressing PMI (j) were treated with 25 mM mannose for the indicated times in the presence or absence of 20 μM chloroquine (CQ) (4 h). Western blotting was undertaken to detect LC3-B and actin. The data are representative of three independent experiments. k, l, Relative incorporation of 32P UTP (k) or 35S methionine (l) into U2OS-E1a control cells (vector) or U2OS-E1a cells overexpressing PMI (PMI) in the presence or absence of 25 mM mannose. Where indicated, 5 μM actinomycin D was used to inhibit transcription or 100 μg ml−1 cycloheximide was used to inhibit translation. In k, n = 3 independent experiments. In l, n = 3 independent experiments (control and mannose) and n = 2 independent experiments (CHX).m, n, U2OS-E1a cells infected with lentiCRISPR-NTC 1, NTC 2, ATG5 or ATG7 were treated with 25 mM d-(+)-mannose for 72 h. m, The number of cells counted after the 72-h treatment; the results represent the mean of one independent experiment performed in triplicate. n, Western blots show loss of LC3 lipidation and p62 accumulation in ATG5 and ATG7 knockout cells. Data were analysed by two-tailed unpaired t-tests. *P < 0.05, ***P < 0.001. Unless otherwise stated, data are mean ± s.e.m. Source data