Fig. 6

Nf1 deficient SCs are resistant to ATP-dependent growth suppression via arrestins. (a) ATP (100 μM) suppresses WT mSC proliferation; Nf1 −/− mSCs are resistant (p = 0.0005). (b) Non-hydrolyzable ATPγS shows that differential growth suppression in WT versus Nf1−/− mSCs is due to ATP, not breakdown products (p = 0.0007). (c) Calcium signaling in response to ATPγS differs in WT versus Nf1−/− mSCs. Nf1−/− mSCs (blue line) lack the dip in calcium at ~ 7 min which is characteristic in WT mSCs (black line, arrow). (d) qRTPCR analysis of the arrestins and P2Y2 between littermate matched pairs (n = 3/3), both arrestins were upregulated in the Nf1−/− setting; however, P2y2 RNA levels were unchanged. (e) Western blot analysis of arrestin and P2y2 levels in WT and KO mSCs, littermate matched pairs (n = 3/3) (f) After ATPγS treatment, western blot in Nf1−/− mSCs show increases in pERK 1/2 and pSer473 Akt at early time points, similar to but reduced from WT mSCs. No decrease in pThr308 Akt was observed