Grant R. Bowman

Learn More
We isolated a dominant gain-of-function Arabidopsis mutant, accelerated cell death 6 (acd6), with elevated defenses, patches of dead and enlarged cells, reduced stature, and increased resistance to Pseudomonas syringae. The acd6-conferred phenotypes are suppressed by removing a key signaling molecule, salicylic acid (SA), by using the nahG transgene, which(More)
Bacterial replication origins move towards opposite ends of the cell during DNA segregation. We have identified a proline-rich polar protein, PopZ, required to anchor the separated Caulobacter crescentus chromosome origins at the cell poles, a function that is essential for maintaining chromosome organization and normal cell division. PopZ interacts(More)
The commonly used, monomeric EYFP enabled imaging of intracellular protein structures beyond the optical resolution limit ('super-resolution' imaging) in living cells. By combining photoinduced activation of single EYFP fusions and time-lapse imaging, we obtained sub–40 nm resolution images of the filamentous superstructure of the bacterial actin protein(More)
The bacterium Caulobacter crescentus has morphologically and functionally distinct cell poles that undergo sequential changes during the cell cycle. We show that the PopZ oligomeric network forms polar ribosome exclusion zones that change function during cell cycle progression. The parS/ParB chromosomal centromere is tethered to PopZ at one pole prior to(More)
The formation of dense core secretory granules is a multistage process beginning in the trans Golgi network and continuing during a period of granule maturation. Direct interactions between proteins in the membrane and those in the forming dense core may be important for sorting during this process, as well as for organizing membrane proteins in mature(More)
In addition to a family of structurally related proteins encoded by the Granule lattice (GRL) genes, the dense core granules in Tetrahymena thermophila contain a second, more heterogeneous family of proteins that can be defined by the presence of a domain homologous to beta/gamma-crystallins. The founding members of the family, Induced during Granule(More)
In some cells, the polypeptides stored in dense core secretory granules condense as ordered arrays. In ciliates such as Tetrahymena thermophila, the resulting crystals function as projectiles, expanding upon exocytosis. Isolation of granule contents previously defined five Granule lattice (Grl) proteins as abundant core constituents, whereas a functional(More)
Bacterial cells are highly organized with many protein complexes and DNA loci dynamically positioned to distinct subcellular sites over the course of a cell cycle. Such dynamic protein localization is essential for polar organelle development, establishment of asymmetry, and chromosome replication during the Caulobacter crescentus cell cycle. We used a(More)
Despite their relative simplicity, bacteria have complex anatomy at the subcellular level. At the cell poles of Caulobacter crescentus, a 177-amino acid (aa) protein called PopZ self-assembles into 3D polymeric superstructures. Remarkably, we find that this assemblage interacts directly with at least eight different proteins, which are involved in cell(More)
The formation of dense core granules (DCGs) requires both the sorting of granule contents from other secretory proteins and a postsorting maturation process. The Tetrahymena thermophila strain SB281 fails to synthesize DCGs, and previous analysis suggested that the defect lay at or near the sorting step. Because this strain represents one of the very few(More)