Filament-forming GTP-binding protein. Lacks GTPase activity, which is likely due to absence of an essential threonine residue important for hydrolytic activity in septins. May be involved in membrane remodeling, potentially by its nucleotide-dependent cellular membrane association/dissociation ability (PubMed:24464615). Able to bind to phosphatidylinositol-4,5-bisphosphate (PIP2)-containing giant unilamellar vesicles (GUVs), which serve as a model of biological membranes. Self-assembles into ordered cage-like structures on the vesicle membrane. Binds also to 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS)-containing vesicles suggesting the requirement for negatively charged membranes. Is also able to promote deformation of the GUVs (PubMed:27687162). Mg(2+) is essential for the GTP-binding, but GDP-binding does not require a metal cofactor. Stable at wide pH range from 4 to 9. Temperature-sensitive. Stable at 15 degrees Celsius. Starts to aggregate at 37 degrees Celsius. Septins polymerize into heterooligomeric protein complexes that form filaments, and can associate with cellular membranes, actin filaments and microtubules (By similarity). Homodimer (PubMed:27687162, PubMed:24464615). Homooligomerizes (PubMed:27687162). Forms (via GTP-binding domain) heterodimers with SEPT5 (via GTP-binding domain) in a nucleotide-dependent manner with GTP promoting heterodimerization most efficiently (PubMed:27687162). Component of the filamentous forming heterocomplex composed of SEPT10, SEPT5 and SEPT7.2 (PubMed:24768753, PubMed:27687162). Heterocomplex formation and the filamentous polymerization of the complexes is enhanced by forchlorfenuron (FCF), a synthetic phenylurea cytokinin (PubMed:24768753). The heterocomplex is able to bind on the membranes of the phosphatidylinositol-4,5-bisphosphate (PIP2)-containing giant unilamellar vesicles (GUVs), which serve as a model of biological membranes (PubMed:27687162). Colocalizes with actin in the longitudinal and circular muscles of the sporocyst. Expressed throughout the developmental cycle of the schistosome, with the highest expression in 14-day old schistosomula. Expressed in superficial structures of the miracidia and sporocysts, with high expression in ciliated epidermal plates of the miracidium, and in the longitudinal and circular muscles of the sporocyst. High expression also in the optical sections of germ cells in miracidia and 2-day old sporocysts. Expressed along the protonephridial ducts of the cercaria, extending laterally nearly the whole length on both sides of the larva. More specifically expressed at the collecting tubules of this osmoregulatory system. Expressed ubiquitously in the schistosomulum. In adults, expression is higher in males than in females. C-terminus (307-412) is necessary for binding to liposomal membranes as assessed by phosphatidylinositol-4,5-bisphosphate (PIP2)-containing giant unilamellar vesicles (GUVs), models of biological membranes. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. Septin GTPase family.