Determining protein polarization proteome-wide using physical dissection of individual Stentor coeruleus cells.

Cellular components are non-randomly arranged with respect to the shape and polarity of the whole cell. Patterning within cells can extend down to the level of individual proteins and mRNA. But how much of the proteome is actually localized with respect to cell polarity axes? Proteomics combined with cellular fractionation has shown that most proteins localize to one or more organelles but does not tell us how many proteins have a polarized localization with respect to the large-scale polarity axes of the intact cell.

Coordinate genomic association of transcription factors controlled by an imported quorum sensing peptide in Cryptococcus neoformans.

Qsp1 is a secreted quorum sensing peptide required for virulence of the fungal meningitis pathogen Cryptococcus neoformans. Qsp1 functions to control cell wall integrity in vegetatively growing cells and also functions in mating. Rather than acting on a cell surface receptor, Qsp1 is imported to act intracellularly via the predicted oligopeptide transporter Opt1.

Aurora kinase inhibitors delay regeneration in at an intermediate step.

The giant unicellular ciliate Stentor coeruleus can be cut into pieces and each piece will regenerate into a healthy, full-sized individual. The molecular mechanism for how Stentor regenerates is a complete mystery, however, the process of regeneration shows striking similarities to the process of cell division. On a morphological level, the process of creating a second mouth in division or a new oral apparatus in regeneration have the same steps and occur in the same order.

Intracellular Action of a Secreted Peptide Required for Fungal Virulence.

Quorum sensing (QS) is a bacterial communication mechanism in which secreted signaling molecules impact population function and gene expression. QS-like phenomena have been reported in eukaryotes with largely unknown contributing molecules, functions, and mechanisms. We identify Qsp1, a secreted peptide, as a central signaling molecule that regulates virulence in the fungal pathogen Cryptococcus neoformans.