Eukaryotic cells are organized in three dimensions to allow for both cell division and for them to perform their physiological functions. This organization is dependent upon the arrangement of the cytoskeleton, which can either generate force by subunit polymerization or serve as tracks for molecular motors to deliver protein complexes, RNAs, or membrane-bound compartments. In general, long-range transport is mediated by microtubules, whereas microfilaments often contribute more local structural and motile roles, being especially prominent in association with the plasma membrane. Microtubules and microfilaments can be quite dynamic, and this requires the appropriate spatial regulation of polymer assembly, then association with factors to generate functional structures, and also control of polymer disassembly. For microfilaments, two major nucleators of actin assembly are the actin-related protein 2/3 (Arp2/3) complex, which generates branched filaments and formins that generate unbranched filaments (1). Formins are present in all eukaryotes—humans have 15 different ones—so understanding their biology is of significant importance. Miao et al. (2) have now established a formin-dependent actin cable assembly reaction using yeast cell extracts that will permit a dissection of how formin activity is regulated in vivo.