Coordinate action of distinct sequence elements localizes checkpoint kinase Hsl1 to the septin collar at the bud neck in Saccharomyces cerevisiae.

摘要: Passage through the eukaryotic cell cycle requires processes that are tightly regulated both spatially and temporally. Surveillance mechanisms (checkpoints) exert quality control impose order on timing organization of downstream events by impeding progression until necessary components available undamaged have acted in proper sequence. In budding yeast, a checkpoint exists does not allow timely execution G2/M transition unless collar septin filaments has properly assembled at bud neck, which is site where subsequent cytokinesis will occur. An essential component this large (1518-residue) protein kinase Hsl1, localizes to neck only if been correctly formed. Hsl1 reportedly interacts with particular septins; however, precise molecular determinants responsible for its recruitment cellular location during G2 elucidated. We performed comprehensive mutational dissection accompanying image analysis identify sequence elements within localization septins neck. Unexpectedly, we found targeting multipartite. A segment central region (residues 611-950), composed two tandem, semiredundant but distinct septin-associating elements, sufficient binding vitro vivo. However, addition 611-950, efficient obligatorily generalized cytosolic face plasma membrane, function normally provided C-terminal phosphatidylserine-binding KA1 domain 1379-1518) can be replaced other, heterologous sequences.