Differential distribution of the endoplasmic reticulum network in filamentous fungi.

Filamentous fungi are composed of hyphal compartments divided by septa, which communicate via septal pores. Apical compartments can elongate to over 100 microm without septum formation and possess a polarized distribution of organelles. In Aspergillus, subapical compartments are arrested in interphase but can reinitiate mitosis and growth by branching. Recent reports using green fluorescent protein (GFP) technology have demonstrated the highly differentiated localization of the endoplasmic reticulum (ER) network in various regions of the hyphae: the gradient distribution from the apical region, the localization along the septum, differential distributions in adjacent compartments, and the dynamic morphological change during septum formation. In this review the spatial regulation of the ER network in multicellular filamentous fungi is discussed.