| Modification Notes |
The centrosome is the primary microtubule organizing center (MTOC) in animal cells and also functions to regulate cell-cycle progression. Centrosomes are made up of a centriole pair that is encompassed by a matrix of pericentriolar material (PCM) which anchors microtubule nucleation sites and therefore controls the amount and organization of microtubules in interphase and mitotic cells. Spindle assembly abnormal proteins 4, 5 and 6 (SAS-4, -5 and -6) represent coiled-coil proteins that are essential for Caenorhabditis elegans centriole formation. SAS-4 is incorporated into centrioles during centriole duplication and remains there throughout the cell cycle. The amount of SAS-4 present is directly correlated with centrosome size, and in the absence of SAS-4, centriole duplication fails. Tube formation and elongation requires the presence of SAS-5 and SAS-6, while the assembly of singlet microtubules onto the central tube depends on SAS-4. |
