%0 Journal Article %J Elife %D 2017 %T The AP-2 complex has a specialized clathrin-independent role in apical endocytosis and polar growth in fungi. %A Martzoukou, Olga %A Amillis, Sotiris %A Zervakou, Amalia %A Christoforidis, Savvas %A Diallinas, George %X Filamentous fungi provide excellent systems for investigating the role of the AP-2 complex in polar growth. Using Aspergillus nidulans, we show that AP-2 has a clathrin-independent essential role in polarity maintenance and growth. This is in line with a sequence analysis showing that the AP-2 β subunit (β2) of higher fungi lacks a clathrin-binding domain, and experiments showing that AP-2 does not co-localize with clathrin. We provide genetic and cellular evidence that AP-2 interacts with endocytic markers SlaB(End4) and SagA(End3) and the lipid flippases DnfA and DnfB in the sub-apical collar region of hyphae. The role of AP-2 in the maintenance of proper apical membrane lipid and cell wall composition is further supported by its functional interaction with BasA (sphingolipid biosynthesis) and StoA (apical sterol-rich membrane domains), and its essentiality in polar deposition of chitin. Our findings support that the AP-2 complex of dikarya has acquired, in the course of evolution, a specialized clathrin-independent function necessary for fungal polar growth. %B Elife %V 6 %8 2017 Feb 21 %G eng %1 http://www.ncbi.nlm.nih.gov/pubmed/28220754?dopt=Abstract %R 10.7554/eLife.20083