Interactive Computer Simulations as Pedagogical Tools in Biology Labs.

Student learning in biology may be impaired by instructional environments that emphasize technical methodology over analysis. We hypothesized that time gained by experimenting with accurate computer simulations could be used to engage students in analytical, creative learning. The effects of treatments that combined a week of simulated lab instruction with a week of standard lab instruction in different order (E-to-S and S-to-E) were examined using a controlled experimental design with random assignment of lab sections and hierarchical linear modeling analysis to account for possible clustering within sections.

Pan1 regulates transitions between stages of clathrin-mediated endocytosis.

Endocytosis is a well-conserved process by which cells invaginate small portions of the plasma membrane to create vesicles containing extracellular and transmembrane cargo proteins. Dozens of proteins and hundreds of specific binding interactions are needed to coordinate and regulate these events. Saccharomyces cerevisiae is a powerful model system with which to study clathrin-mediated endocytosis (CME).

Targeted disruption of an EH-domain protein endocytic complex, Pan1-End3.

Pan1 is a multi-domain scaffold that enables dynamic interactions with both structural and regulatory components of the endocytic pathway. Pan1 is composed of Eps15 Homology (EH) domains which interact with adaptor proteins, a central region that is responsible for its oligomerization and C-terminal binding sites for Arp2/3, F-actin, and type-I myosin motors. In this study, we have characterized the binding sites between Pan1 and its constitutive binding partner End3, another EH domain containing endocytic protein.

Quantitative analysis of endocytosis with cytoplasmic pHluorin chimeras.

The pH-sensitive green fluorescent protein (GFP) variant pHluorin is typically fused to the extracellular domain of transmembrane proteins to monitor endocytosis. Here, we have turned pHluorin inside-out, and show that cytoplasmic fusions of pHluorin are effective quantitative reporters for endocytosis and multivesicular body (MVB) sorting. In yeast in particular, fusion of GFP and its variants on the extracellular side of transmembrane proteins can result in perturbed trafficking.