Proinsulin Promotes Self-Renewal of a Hematopoietic Progenitor Cell Line In Vitro

Figure 2

Signaling pathway mediated by the insulin receptor (IR) activated by proinsulin. (a) Serum-starved MEF cells (for 12 h) were stimulated with insulin, 20% CM of EML/empty, and 20% CM of EML/Pro-INS, respectively, for 10 min. Then, the cells were harvested and lysed in RIPA buffer. The phosphorylated β-subunit of IR (IRβ) and phosphorylated Akt were detected via Western blotting. (b) Serum-starved MEF cells (for 12 h) were exposed to insulin for 10 min and increasing doses of CM of EML/Pro-INS, respectively. The phosphorylated IRβ was detected via Western blotting. The ratio of the gray density of phosphor-IRβ versus total IRβ was measured and calculated. (c), (d) The levels of IR and Glut1 mRNA expression in MEF cells stimulated with 20% CM of EML/empty and 20% CM of EML/Pro-INS, respectively, were detected using real-time PCR.

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