In the cohesive structure of actin cytoskeleton, functionally distinct actin arrays orchestrate fundamental cell functions in a spatiotemporally controlled manner. Emerging evidences emphasize that the fine-tuning of these regulatory mechanisms involves the actions and interactions of various protein isoforms, however the underlying molecular mechanisms are not completely understood. The ultimate aim of our research is to better understand the complex and manifold regulation of the diverse functions of the actin cytoskeleton. To describe these aspects of the cytoskeleton we study one of the major cell architecture components, actin, and one of its most abundant partner proteins, tropomyosins. The specific aim of our research is to dissect the molecular mechanisms that drive the segregation of functionally different sub-cellular complexes and links actin and tropomyosin isoforms to the biological diversity related to actin network functions. To address this issue we investigate how the assembly dynamics, morphology, molecular composition and the functional characteristics of the actin-tropomyosin supramolecular structures depend on the isoform content. We use a novel experimental strategy based on an interdisciplinary arsenal of approaches involving molecular and cell biology, protein biochemistry techniques in combination with complementary biophysical and biomimetic assays.