Ninein Like Protein (NINL)

NLP contains 2 N-terminal EF-hand Ca(2+)-binding domains, followed by 3 central coiled-coil domains and a larger C-terminal coiled-coil domain. NLP does not have the GTP-binding site present in ninein. The N-terminal half of NLP, which shares highest similarity with ninein, has 8 potential PLK1 phosphorylation sites. Immunofluorescence microscopy of human cell lines detected NLP at centrosomes, where staining substantially overlapped that of gamma-tubulin . NLP appeared to concentrate in distinct dots surrounding primarily 1 of the 2 centrioles. An NLP mutant lacking PLK1 phosphorylation sites was able to recruit gamma-tubulin and stimulate microtubule nucleation, but it was unable to dissociate from centrosomes, resulting in aberrant mitotic spindle formation.