Within every mammalian cell, the actin cytoskeleton forms networks composed of multiple filaments that support numerous fundamental cellular functions, such as cell division, motility, and intracellular transport. Myosin molecular motors use ATP hydrolysis to exert power strokes onto actin filaments. This phenomenon is up-scaled and applied to large assembly of filaments in actin networks inside cells, and leads to active chiral phenomenons. These are at the base of many large scale processes, such as the asymmetric development of multi-cellular organisms. Identifying the coupling between physico-chemical and geometrical parameters in acto-myosin networks to better understand active chiral processes is thus one of the most fundamental problem in biology. To investigate this we focus our effort on the study of the emergence of rotational chirality in polar actin bundles. We propose bottom-up approaches to decipher individual molecular events and how they synergize to drive collective activity at the meso-scale. We will combine original experimental design to study motor-filament interactions using minimal reconstitution systems, with purified proteins. We will use a combination of fluorescence microscopy, microfluidics, and magnetic tweezers, which allows us to precisely control biochemical conditions and apply physiologically relevant forces in order to quantify the interactions between the filaments and various regulatory proteins.