Tropomyosin isoforms regulate distinct cellular pathways in undifferentiated and differentiated B35 neuroblastoma cells

Tropomyosins are a family of actin-associated proteins that modulate actin filament stability and dynamics by regulating the activity and binding of other actin-associated proteins to actin filaments. The association of different tropomyosin isoforms with actin filaments, bestows the filaments distinct biochemical and physical properties which are important for determining cell shape and regulating a large number of cellular processes in eukaryotic cells. Although pervious studies have identified several structural and regulatory proteins that are functionally linked to tropomyosins, a comprehensive analysis of global changes in eukaryotic cells in response to altered expression of distinct tropomyosin isoforms is still lacking. Here, we used RNA-seq to investigate the effect of four tropomyosin isoforms on gene expression in undifferentiated and differentiated rat B35 neuroblastoma cells. In undifferentiated cells, overexpression of tropomyosin isoforms 1.12, 2.1, 3.1 and 4.2 differentially regulate a vast number of genes (DEGs). These DEGs clustered into a several GO terms, including a pathway of actin-binding proteins. In differentiated cells, tropomyosin overexpression exerts a weaker influence on overall gene expression with Tpm3.1 being the only isoform, generating GO terms. Overall, this study highlights the regulatory role of different tropomyosin isoforms, influencing distinct cellular processes.