Recombinant full-length human MSSK1 was expressed by baculovirus in Sf9 insect cells using an N-terminal GST tag. MSSK1, also known as SRPK3, is a muscle-specific protein kinase belonging to the serine arginine protein kinase family, which phosphorylates serine/arginine repeat-containing proteins. Heart and skeletal muscle show high expression of the MSSK1/SRPK3 gene product. SRPK3-null mice display a new entity of type 2 fiber-specific myopathy with a marked increase in centrally placed nuclei. Transgenic mice overexpressing SRPK3 in skeletal muscle show severe myofiber degeneration and early lethality. ADP-Glo Kinase Assay is a luminescent kinase assay that measures ADP formed from a kinase reaction; ADP is converted into ATP, which is a substrate in a reaction catalyzed by Ultra-Glo Luciferase that produces light. The luminescent signal positively correlates with ADP amount and kinase activity. The assay is well suited for measuring the effects chemical compounds have on the activity of a broad range of purified kinases, making it ideal for both primary screening as well as kinase selectivity profiling. The ADP-Glo Kinase Assay can be used to monitor the activity of virtually any ADP-generating enzyme (e.g., kinase or ATPase) using up to 1mM ATP.