septin-2; neural cell expressed developmentally down-regulated protein 5; NEDD-5 (SEPT2, DIFF6, KIAA0158, NEDD5)

Function: - filament-forming cytoskeletal GTPase - required for normal organization of the actin cytoskeleton - role in biogenesis of polarized columnar-shaped epithelium by maintaining polyglutamylated microtubules, thus facilitating efficient vesicle transport, & by impeding MAP4 binding to tubulin - required for progression through mitosis - forms a scaffold at the midplane of the mitotic splindle - required to maintain CENPE localization at kinetochores & consequently chromosome congression - during anaphase, may be required for chromosome segregation & spindle elongation - may play a role in the internalization of intracellular microbial pathogens, including Listeria monocytogenes & Shigella flexneri - septins polymerize into heterooligomeric protein complexes that form filaments, & associate with cellular membranes, actin filaments & microtubules - GTPase activity is required for filament formation - ilaments are assembled from asymmetrical heterotrimers, composed of SEPT2, SEPT6 & SEPT7 that associate head-to-head to form a hexameric unit - interaction between SEPT2 & SEPT7 seems indirect - interacts with SEPT5 - interaction with SEPT4 not detected (putative) - interacts with SEPT9 - interacts with MAP4 Structure: belongs to the septin family Compartment: - cytoplasm, cytoskeleton - spindle, chromosome, centromere, kinetochore - cleavage furrow, midbody - in metaphase cells, localized within the microtubule spindle - at the metaphase plate, in close apposition to the kinetochores of the congressed chromosomes - in cells undergoing cytokinesis, localized to the midbody, the ingressing cleavage furrow, & the central spindle - during bacterial infection, displays a collar shape structure next to actin at the pole of invading bacteria - in epithelial cells, colocalizes with polyglutamylated tubulin around the trans-Golgi network, as well as juxatnuclear & proximal Golgi apparatus Alternative splicing: named isoforms=2 Expression: - widely expressed - up-regulated in liver cancer - coordinated expression with SEPT6 & SEPT7

General

phosphoprotein septin

Properties

SIZE: entity length = 361 aa MW = 41 kD COMPARTMENT: cytoplasm cell nucleus golgi MOTIF: Tyr phosphorylation site {Y17} GTP-binding site SITE: 44-51 GTP-binding site SITE: 78-78 GTP-binding site SITE: 104-104 phenylalanine residue {156} GTP-binding site SITE: 183-191 Tyr phosphorylation site {Y211} Ser phosphorylation site {S218} Thr phosphorylation site {T228} GRP-BINDING-SITE :ENGLISH binding via amide nitrogen :SITE RANGE :LOW 241 :HIGH 241 GTP-binding site SITE: 256-256 Role in dimerization {260-270}

Database Correlations

OMIM 601506 UniProt Q15019 Pfam PF00735 Entrez Gene 4735 Kegg hsa:4735