SMPD1 and Miyoshi myopathy: Of note, ASM activity in MM cells can be stimulated by epigallocatechin-3-O-gallate-induced production of cyclic guanosine monophosphate (cGMP), leading to activation of PLCγ and subsequent activation of protein kinase Cδ (PKCδ), suggesting FGF/FGFR signaling can induce ASM activity through PLCγ [215].