Col6a1^−/− Mks and platelets maintain SOCE alterations after BM transplantation in a WT background. (Ai) qRT-PCR analysis of STIM1 and ORAI1 mRNA expression in sorted BM Mks from WT recipient mice after BM transplantation with WT (WT→WT) or Col6a1^−/− (Col6a1^−/−→WT) Lin⁻ BM cells. Data are mean ± SD (WT→WT, n = 5; Col6a1^−/→WT, n = 3). Student t test. (Aii) Flow cytometry analysis of STIM1 and ORAI1 protein levels in BM Mks from WT recipient mice after BM transplantation, as in (i). Data are mean ± SD (WT→WT, n = 5; Col6a1^−/−→WT, n = 3). Student t test. (Bi) Western blot for STIM1 and ORAI1 in platelets isolated from WT recipient mice after BM transplantation with WT or Col6a1^−/− Lin⁻ BM cells, as in (A). β-Actin was used as a loading control. (Bii) Band densities were quantified and expressed relative to WT→WT. Data are mean ± SD (WT→WT, n = 5; Col6a1^−/−→WT, n = 3). Student t test. (C) Platelet activation measured as integrin αIIbβ3 activation (i) and CD62P cell surface exposure (ii) after stimulation with 0.1 U/mL thrombin (Thr), 25 μM ADP, or 20 ng/mL CVX in platelets isolated from WT recipient mice after transplantation with WT or Col6a1^−/− Lin⁻ BM cells. Data are mean ± SD (WT→WT, n = 5; Col6a1^−/−→WT, n = 4). Student t test. *P < .05, **P < .01. MFI, mean fluorescence intensity.