FunctionFilament-forming cytoskeletal GTPase (By similarity). May play a role in cytokinesis (Potential). May play a role in the internalization of 2 intracellular microbial pathogens, Listeria monocytogenes and Shigella flexneri.
Tissue specificityWidely expressed. Isoforms are differentially expressed in testes, kidney, liver heart, spleen, brain, peripheral blood leukocytes, skeletal muscle and kidney. Specific isoforms appear to demonstrate tissue specificity. Isoform 5 is the most highly expressed in fetal tissue. Isoform 1 is detected in all tissues except the brain and thymus, while isoform 2, isoform 3, and isoform 4 are detected at low levels in approximately half of the fetal tissues.
Involvement in diseaseNote=A chromosomal aberration involving SEPT9/MSF is found in therapy-related acute myeloid leukemia (t-AML). Translocation t(11;17)(q23;q25) with MLL. Defects in SEPT9 are a cause of hereditary neuralgic amyotrophy (HNA) [MIM:162100]; also known as neuritis with brachial predilection (NAPB) or hereditary brachial plexus neuropathy or hereditary neuralgic amyotrophy with predilection for brachial plexus. HNA is an autosomal dominant form of recurrent focal neuropathy characterized clinically by acute, recurrent episodes of brachial plexus neuropathy with muscle weakness and atrophy preceded by severe pain in the affected arm. HNA is triggered by environmental factors such as infection or parturition.
Sequence similaritiesBelongs to the septin family.
Cellular localizationCytoplasm > cytoskeleton. In an epithelial cell line, concentrates at cell-cell contact areas. After TGF-beta1 treatment and induction of epithelial to mesenchymal transition, colocalizes partly with actin stress fibers. During bacterial infection, displays a collar shape structure next to actin at the pole of invading bacteria.