A universally important aspect of growth and development is the integration of mitosis with cell division. This helps ensure that cells maintain their normal size, shape and nuclear number, which in the fungi can vary considerably. For example, the highly polarized mode of growth of the filamentous fungi is subject to complex developmental regulation yielding diverse cell types containing from one to dozens of nuclei. How fungi integrate the regulation of the developmental axis involving mitosis, cytokinesis, and morphogenesis to maintain their defined cellular shapes, with distinctive numbers of nuclei, remains a mystery. However, recent studies of the mitotic NIMA kinase indicates it plays additional non-mitotic cytoplasmic functions in Aspergillus nidulans that impinge on fungal development. These insights were derived initially from defining the interphase subcellular locations of NIMA which revealed it locates to both forming and mature septa and additionally locates to tips of growing interphase cells. Subsequent studies revealed that septal pores are subject to cell cycle regulation which prevents cytoplasmic movement between mitotic cell compartments and their adjacent interphase partners. We further find that NIMA markedly affects the regulation of cell tip dominance and morphology via a mechanism involving NIMA location at microtubule +ends and the modulation of interphase cytoskeletal functions. Collectively the findings indicate that the mitotic NIMA kinase has roles to regulate communication between adjacent hyphal cells as well as cytoskeletal functions important for normal tip cell growth. Thus NIMA has the potential to help integrate nuclear division with cell division and morphogenesis.
Full conference title:
27th Fungal Genetics Conference
- FGC 27th (2013)