SPAG5 Antibody - #DF9944

Essential component of the mitotic spindle required for normal chromosome segregation and progression into anaphase. Required for chromosome alignment, normal timing of sister chromatid segregation, and maintenance of spindle pole architecture. In complex with SKAP, promotes stable microtubule-kinetochore attachments. May contribute to the regulation of separase activity. May regulate AURKA localization to mitotic spindle, but not to centrosomes and CCNB1 localization to both mitotic spindle and centrosomes. Involved in centriole duplication. Required for CDK5RAP2, CEP152, WDR62 and CEP63 centrosomal localization and promotes the centrosomal localization of CDK2. In non-mitotic cells, upon stress induction, inhibits mammalian target of rapamycin complex 1 (mTORC1) association and recruits the mTORC1 component RPTOR to stress granules (SGs), thereby preventing mTORC1 hyperactivation-induced apoptosis. May enhance GSK3B-mediated phosphorylation of other substrates, such as MAPT/TAU.

Phosphorylated by AURKA.

Cytoplasm. Cytoplasm>Cytoskeleton. Cytoplasm>Cytoskeleton>Spindle. Cytoplasm>Cytoskeleton>Spindle pole. Chromosome>Centromere>Kinetochore. Midbody. Cytoplasm>Cytoskeleton>Microtubule organizing center>Centrosome. Cytoplasmic granule. Cytoplasm>Cytoskeleton>Microtubule organizing center>Centrosome>Centriolar satellite.
Note: Colocalizes with PCM1 at centriolar satellites throughout the cell cycle (PubMed:26297806). In a punctate pattern in interphase cells. During mitosis, detected at spindle poles during prophase, throughout the spindle in metaphase and anaphase, and at midzone microtubules in anaphase and telophase (PubMed:27462074). Efficient targeting to the mitotic spindle may depend upon phosphorylation by GSK3B. Detected on kinetochores of chromosomes that have congressed. The astrin (SPAG5)-kinastrin (SKAP) complex localizes to the microtubule plus ends (By similarity). In non-mitotic non-stressed cells, shows a microtubuli pattern. In arsenite-stressed cells, accumulates in stress granules.

Highly expressed in testis. Detected at low levels in placenta, liver, pancreas, thymus and colon.

Homodimer, with a globular head domain and a long stalk. Homooligomer; the globular head domains associate, resulting in aster-like structures. Binds to microtubules in the mitotic spindle. Interacts with DCLRE1B/Apollo. Part of an astrin (SPAG5)-kinastrin (SKAP) complex containing KNSTRN, SPAG5, PLK1, DYNLL1 and SGO2. Interacts with KNSTRN. Interacts with RPTOR; this interaction competes with RPTOR binding to MTOR, resulting in decreased mTORC1 formation. Interacts with G3BP1. The complex formed with G3BP1 AND RPTOR is increased by oxidative stress. Interacts with OSBPL8, PCM1 and CDK5RAP2. Interacts (via C-terminus) with NUMA1 (via C-terminus); this interaction promotes the recruitment of SPAG5 to the microtubules at spindle poles in a dynein-dynactin-dependent manner.