The following text describes a protein:
Function:
Guanine nucleotide exchange factor (GEF) that catalyzes the exchange of GDP for GTP. Promotes guanine nucleotide exchange on the Rho family members of small GTPases, like RHOA, RHOC, RAC1 and CDC42. Required for signal transduction pathways involved in the regulation of cytokinesis. Component of the centralspindlin complex that serves as a microtubule-dependent and Rho-mediated signaling required for the myosin contractile ring formation during the cell cycle cytokinesis. Regulates the translocation of RHOA from the central spindle to the equatorial region. Plays a role in the control of mitotic spindle assembly; regulates the activation of CDC42 in metaphase for the process of spindle fibers attachment to kinetochores before chromosome congression. Involved in the regulation of epithelial cell polarity; participates in the formation of epithelial tight junctions in a polarity complex PARD3-PARD6-protein kinase PRKCQ-dependent manner. Plays a role in the regulation of neurite outgrowth. Inhibits phenobarbital (PB)-induced NR1I3 nuclear translocation. Stimulates the activity of RAC1 through its association with the oncogenic PARD6A-PRKCI complex in cancer cells, thereby acting to coordinately drive tumor cell proliferation and invasion. Also stimulates genotoxic stress-induced RHOB activity in breast cancer cells leading to their cell death.
Miscellaneous:
MISCELLANEOUS: [Isoform 3]: May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.
Subcellular Localization:
Nucleus. Cytoplasm. Cytoplasm, cytoskeleton, spindle. Cleavage furrow. Midbody. Cell junction. Cell junction, tight junction. Note=Sequestered within the nucleus during interphase (By similarity). Dispersed throughout the cytoplasm upon breakdown of the nuclear envelope during mitosis (By similarity). Colocalizes with the centralspindlin complex to the mitotic spindles during anaphase/metaphase, the cleavage furrow during telophase and at the midbody at the end of cytokinesis (By similarity). Colocalized with RhoA at the midbody (By similarity). Its subcellular localization to tight junction is increased by calcium (By similarity).
Domain:
The BRCT domain 1 and 2 are required for the intramolecular interaction, but not for the intermolecular oligomerization. The BRCT domains negatively inhibit its GEF activity in interphase cells. The same BRCT domains may act as a positive regulatory motif for the completion of cytokinesis after the breakdown of nuclear membrane during mitosis (By similarity).
Sequence:
MADDSVLPSPSEITSLADSSVFDSKVAEMSKENLCLASTSNVDEEMPQVEARVIMVQDAGKQEELLKALKTIKIMEVPVIKIKESCPGKSEEKLIKSIINMEMKVPCVKMDSMEEFESLDSPEFENIFVVTDFQNSVFNDLYKADCRIVGPPVILNCAQRGEPLPFSCRPLYCTSMLNLVLCFTGFRKKEELVKLVTLVHHMGGVIRKECNSKVTHLVANCTQGEKFRVAVSLGTPIMKPEWIYKAWERRNEQCFCAAVDDFRNEFKVPPFQDCILSFLGFSDEEKHSMEEMTEMQGGSYLPVGDERCTHLIVEENTVKDLPFEPSKKLFVVKQEWFWGSIQMDARAGETMYLYEKANTPELKKSVSLLSLSTPNSNRKRRRLKETLAQLSRETDLSPFPPRKRPSAEHSLSIGSLLDISNTPESSIHYGETPKSCAKSSRSSTPVPPKQSARWQVAKELYQTESNYVNILATIIQLFQVPLEEEGQRGGPILAPEEIKTIFGSIPDIFDVHMKIKDDLEDLIANWDESRSIGDIFLKYAKDLVKTYPPFVNFFEMSKEMIIKCEKQKPRFHAFLKINQAKPECGRQSLVELLIRPVQRLPSVALLLNDLKKHTADENPDKSTLEKAIGSLKEVMTHINEDKRKTEAQKQIFDVVYEVDGCPANLLSSHRSLVQRVETVSLGEHPCDRGEQVTLFLFNDCLEIARKRHKVIGTFRSPHDRTRPPASLKHIHLMPLSQIKKVLDIRETEDCHNAFALLVRPPTEQANVLLSFQMTSEELPKESWLKMLCRHVANTICKADAENLMYVADPESFEVNTKDMDSTLSRASRAIKKTSKKVTRAFSFSKTPKRALRMALSSSHSSEGRSPPSSGKLAVSRLSSTSSLAGIPSPSLVSLPSFFERRSHTLSRSTTHLI