Figure 7.

cMyBP-C^ΔC10mut protein is highly soluble and localizes at the Z-line in the cardiac sarcomere. (A) Western blot analysis depicting the levels of total soluble cMyBP-C (endogenous and/or cMyBP-C^ΔC10mut) from cMyBP-C^ΔC10mut and NTG hearts (n = 4 NTG, 5 cMyBP-${\mathrm{C}}_{,}^{\text{Δ}\mathrm{C}10\text{mut}}$ *P < 0.027). (B) Single cardiomyocytes were isolated from cMyBP-C^ΔC10mut and NTG hearts and were stained with antibodies detecting cMyBP-C’s N-terminus (C0 domain) (green) and α-actinin (red). In both NTG and cMyBP-C^ΔC10mut myocytes, the classical staining pattern of two cMyBP-C bands between Z-lines (stained with α-actinin) was observed, indicating proper localization of endogenous cMyBP-C in cMyBP-C^ΔC10mut and NTG cardiomyoctyes. (C) Cardiomyocytes from cMyBP-C^ΔC10mut and NTG hearts were stained with antibodies to detect c-Myc (blue), which will show only the c-Myc-tagged cMyBP-C^ΔC10mut protein and α-actinin (red). The c-Myc signal was only observed in myocytes from cMyBP-C^ΔC10mut hearts. The presence of c-Myc staining at the Z-line with α-actinin suggests that the cMyBP-C^ΔC10mut protein aberrantly distributes within the cardiac sarcomere in cMyBP-C^ΔC10mut myocytes. Scale bar = 5 μm in B and C.