Myosin and actin are two crucial contractile proteins that make up the sarcomere and aid in cardiac muscle contraction. Myosin folding is carried out with the help of molecular chaperones such as UNC-45. UNC-45 is a UCS domain that is expressed in mammals and several organisms which likely aids in myosin folding and accumulation. The isoform UNC-45B has been reported to be exclusively expressed in striated muscle. Structurally, UNC-45 is made up of three identified regions: N-terminal TPR domain, central domain, and a C-terminal UCS domain The TPR domain has been evolutionary conserved in several species such as Homo sapiens and rat. A novel heterozygous missense mutation in exon 3 of UNC-45B was discovered, leading to substitution of a highly conserved glutamine to lysine. The variant UNC-45 was identified in several affected individuals of a three-generation family with hypertrophic cardiomyopathy. This study utilized a variant of Unc-45b using primary rat cardiomyocytes as cell model to determine the pathogenesis of the mutation and its capability to be disease-causing. Primary rat cardiomyocytes were transfected with both wild-type and mutant Unc-45 to highlight any structural differences. Structural analysis was performed through immuno- staining of the contractile components, myosin and actin, as well as GFP-labeling of the Unc-45b protein. To validate the expression of Unc-45 in rat myocytes, western blot was carried out. Immunostaining of contractile components of the sarcomere showed the localization of Unc-45 and its genetic material. However, several staining targets were deemed unsuccessful and no significant results could be interpreted.