HA-1004 is primarily used in biochemical and pharmacological research as a selective inhibitor of protein kinases, particularly targeting cyclic nucleotide-dependent kinases such as PKA and PKG. It serves as a valuable tool for studying signal transduction pathways involving these enzymes. Due to its ability to modulate kinase activity, HA-1004 has been investigated for its potential effects on cellular processes like proliferation, differentiation, and apoptosis. It is also utilized in studies exploring the role of kinase inhibition in smooth muscle relaxation and cardiovascular function. Its application remains confined to experimental settings, mainly in vitro systems, to dissect kinase-mediated mechanisms in disease models.