Elucidating the Role of Paxillin B in Septation in Aspergillus nidulans

Abstract

Paxillin B (PaxB) is a protein found in the fungus Aspergillus nidulans that is suspected to play a role in cell growth and division as a scaffolding protein. We have used GFP tagging to show that PaxB localizes to growing hyphal tips and to sites of septation (sites of cell division). This finding led us to hypothesize that PaxB plays an integral role in growth and division. This hypothesis was supported when we deleted the PaxB gene from the A. nidulans genome and found that formation of septa was impaired. Additionally, we have conducted a complementation experiment in which a functioning copy of the PaxB gene corrected the aseptate phenotype seen in the sepD1 temperature-sensitive strain. Most recently, we generated a strain lacking the PaxB gene while expressing GFP-tagged chitin synthase (ChsA) to show that localization of ChsA to maturing septa is diminished but not completely inhibited. Additionally, we have obtained preliminary evidence identifying potential binding partners to PaxB by utilizing GFP-Trap, a variant of co-immunoprecipitation.