This entry describes M-phase phosphoprotein 6 (MPP6), which is involved in generation of the 3' end of the 5.8S rRNA precursor []. MPP6 is required for the integrity maintenance of the rRNA processing complex as it mediates the interaction between MTR4 (RNA helicase) and RRP6 (an 3'-5' exonuclease), and the recruitment of Nuclear VCP-like 2 (NVL2) to the nuclear exosome [].
This entry represents the SH3 domain of MPP6 (also known as VAM-1), which is a scaffolding protein that binds to Veli-1, a homologue of Caenorhabditis Lin-7 []. MPP6 belongs to the membrane-associated guanylate kinase (MAGUK) p55 subfamily.The membrane-associated guanylate kinase (MAGUK) p55 subfamily (also known as MPP subfamily) members include the Drosophila Stardust protein and its vertebrate homologues, MPP1-7. They contain the core of three domains characteristic of MAGUK (membrane-associated guanylate kinase) proteins: PDZ, SH3, and guanylate kinase (GuK). In addition, they also contain the Hook (Protein 4.1 Binding) motif in between the SH3 and GuK domains []. MPP2-7 have two additional L27 domains at their N terminus. The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain [].
