RNA binding proteins (RBPs) play critical roles in regulating the post-transcriptional gene expression in mammalian cells. RBPs intimately interact and alter the activity and stability of multiple RNA species, including modulation of messenger(m)RNA functions. Many RBPs are known to associate with pathological conditions such as neuropathies, metabolic disorders, cancer, muscular atrophy and often cardiac pathologies such as dilated cardiomyopathy and myotonic dystrophy. We have identified hundreds of novel RBPs in cardiomyocytes like HL-1 cells using RNA interactome capture, an ‘omics’ method to discover RBPs via their direct-contact UV-crosslinking and co-purification with mRNA followed by quantitative mass spectrometry. Unexpectedly, our RBP finds included homeostasis-linked proteins of high importance in cardiomyocytes, such as calcium channel protein sarco(endo)plasmic reticulum calcium ATPase 2a (SERCA2a) along with multiple metabolic enzymes. Alterations of the RNA binding domain (RBD) within several RBPs are known to cause pathological conditions. For instance, a deficient RBD of SERCA2a may cause Dariers skin disease. However, the RBP function of these proteins in cardiac (patho)physiology remains obscure. Here we aim at closing this knowledge gap by identifying the interacting RNA partners of the cardiac-critical RBPs such as SERCA2a, Aldolase A, Isocitrate dehydrogenase and Enolase 1, via an unbiased approach based on UV crosslinking of the interacting RNA and proteins, their purification based on affinity to the protein component followed by the sequencing of the attached RNA. Our results will provide models and mechanisms of the cardiac RBP functions and help to better understand cardiac post-transcriptional gene control in heart, opening new possibilities for mitigation of cardiac pathologies.