Figure 5: c-Src promotes glycolytic flux by stimulating HK.

(a) c-Src stimulated glucose uptake by activating HK1 rather than its Y732F mutant. HeLa cells were infected with lentiviruses-expressing proteins indicated. Forty-eight hours post-infection, glucose uptake was measured according to the protocol described in Methods. (b) c-Src enhanced glucose uptake promoted by expression of HK2, but not HK2-Y686F in HeLa cells. (c) Re-expression of HK1 in HeLa cells rescued the decrease of glucose uptake caused by knockdown of endogenous HK1, while HK1-Y732F and HK1-KD showed no effect. (d) The glucose uptake stimulated by HK1 was eliminated by treating HeLa cells with PP2. (e) The augmentation of glucose uptake resulted from HK1 overexpression in HeLa cells was diminished by interference of c-Src expression and further rescued by re-expression of c-Src. (f,g) In HeLa cells PDGF stimulated increase of glucose uptake was diminished by treating cells with PP2 (f) or knockdown of HK1 (g). (h,i) Wild-type HK increased the lactate production and this effect was strengthened by co-expression with c-Src. HeLa cells were infected with different combinations of viruses expressing the proteins indicated. Lactate content was detected with lactate assay kit according to the procedure provided in the Methods. Lactate content of each group was normalized to the group of vector control (bar 1). Values in each panel are means±s.d. of three independent experiments. Unpaired Student’s t-test was used to analyse the significance. **P<0.01, ***P<0.001, N.S. refers to no significant difference.