Septins are conserved, ubiquitous cytoskeletal proteins that have a central role in cell division, cell motility and animal cell morphogenesis. Septins organize into palindromic protomers (hexamers and octamers), which can polymerize into filaments and bind the plasma membrane, as well as actin filaments and microtubules. Although human septin dysfunction is linked to infertility, neurodegenerative diseases and cancer, the molecular mechanisms underlying the function of human septins are not clear. SEPTIMORF aims at elucidating the function of human septins by using animal cell division as a model morphogenetic process whose success depends on septins. Several different septin protomers interact with membranes, actin and microtubules, yet how these different protomers differentially contribute to function is not known. Our central hypothesis is that the type of septin protomer tunes the ability of septins to polymerize and determines their affinity and specificity for membranes, actin filaments and microtubules, and thereby determines septin function. To decipher the link between human septin organization and function and to tease apart the hierarchy of septin interactions with other cytoskeletal elements, SEPTIMORF uniquely combines bottom-up approaches using purified components with functional studies in dividing cells. Our multi-scale interdisciplinary approach will provide a first of its kind comprehensive understanding of how septins functionally organize in human cells thus providing insights into the role of septins in health and disease.