Gerald Weeks

Cyclic AMP signalling in Dictyostelium: G-proteins activate separate Ras pathways using specific RasGEFs (2007)

Kae, Helmut, Kortholt, Arjan, Rehmann, Holger, Insall, Robert H., Spiegelman, George B., ...

In general, mammalian Ras guanine nucleotide exchange factors (RasGEFs) show little substrate specificity, although they are often thought to regulate specific pathways. Here, we provide in vitro and...

Characterization of the GbpD-activated Rap1 Pathway Regulating Adhesion and Cell Polarity in Dictyostelium discoideum (2006)

Kortholt, Arjan, Rehmann, Holger, Kae, Helmut, Bosgraaf, Leonard, Keizer-Gunnink, Ineke, Weeks, Gerald, ...

The regulation of cell polarity plays an important role in chemotaxis. GbpD, a putative nucleotide exchange factor for small G-proteins of the Ras family, has been implicated in adhesion, cell...

A novel DictyosteliumRasGEF required for chemotaxis and development (2005)

Arigoni, Maddalena, Bracco, Enrico, Lusche, Daniel F, Kae, Helmut, Weeks, Gerald, Bozzaro, Salvatore

Abstract Background Ras proteins are guanine-nucleotide-binding enzymes that couple cell surface receptors to intracellular signaling pathways controlling cell proliferation and differentiation, both...

The Small Mr Ras-like GTPase Rap1 and the Phospholipase C Pathway Act to Regulate Phagocytosis in Dictyostelium discoideum

Seastone, David J., Zhang, Linyi, Buczynski, Greg, Rebstein, Patrick, Weeks, Gerald, Spiegelman, George, ...

The function of the small-Mr Ras-like GTPase Rap1 remains largely unknown, but this protein has been demonstrated to regulate cortical actin-based morphologic changes in Dictyostelium and the...

RasC is required for optimal activation of adenylyl cyclase and Akt/PKB during aggregation

Lim, Chinten James, Spiegelman, George B., Weeks, Gerald

Disruption of Dictyostelium rasC, encoding a Ras subfamily protein, generated cells incapable of aggregation. While rasC expression is enriched in a cell type-specific manner during post-aggregative...

Control of Fatty Acid Metabolism I. Induction of the Enzymes of Fatty Acid Oxidation in Escherichia coli

Weeks, Gerald, Shapiro, Martin, Burns, R. O., Wakil, Salih J.

Escherichia coli grows on long-chain fatty acids after a distinct lag phase. Cells, preadapted to palmitate, grow immediately on fatty acids, indicating that fatty acid oxidation in this bacterium is...

Dictyostelium RasD is required for normal phototaxis, but not differentiation

Wilkins, Andrew, Khosla, Meenal, Fraser, Derek J., Spiegelman, George B., Fisher, Paul R., Weeks, Gerald, ...

RasD, a Dictyostelium homolog of mammalian Ras, is maximally expressed during the multicellular stage of development. Normal Dictyostelium aggregates are phototactic and thermotactic, moving towards...

RasC Plays a Role in Transduction of Temporal Gradient Information in the Cyclic-AMP Wave of Dictyostelium discoideum

Wessels, Deborah, Brincks, Rebecca, Kuhl, Spencer, Stepanovic, Vesna, Daniels, Karla J., Weeks, Gerald, ...

To define the role that RasC plays in motility and chemotaxis, the behavior of a rasC null mutant, rasC−, in buffer and in response to the individual spatial, temporal, and concentration components...

A Ras subfamily GTPase shows cell cycle-dependent nuclear localization

Sutherland, Brent W., Spiegelman, George B., Weeks, Gerald

Previously characterized Ras subfamily proteins have been found to be predominantly associated with the plasma membrane where they function in signal transduction pathways to convey extracellular...

Chemoattractant-induced Ras activation during Dictyostelium aggregation

Kae, Helmut, Lim, Chinten James, Spiegelman, George B, Weeks, Gerald

Ras proteins are highly conserved molecular switches that regulate cellular response to external stimuli. Dictyostelium discoideum contains an extensive family of Ras proteins that function in...

Delineation of the Roles Played by RasG and RasC in cAMP-dependent Signal Transduction during the Early Development of Dictyostelium discoideum

Bolourani, Parvin, Spiegelman, George B., Weeks, Gerald

On starvation, the cellular slime mold Dictyostelium discoideum initiates a program of development leading to formation of multicellular structures. The initial cell aggregation requires chemotaxis...

The Small Mr Ras-like GTPase Rap1 and the Phospholipase C Pathway Act to Regulate Phagocytosis in Dictyostelium discoideum

Seastone, David J., Zhang, Linyi, Buczynski, Greg, Rebstein, Patrick, Weeks, Gerald, Spiegelman, George, ...

The function of the small-Mr Ras-like GTPase Rap1 remains largely unknown, but this protein has been demonstrated to regulate cortical actin-based morphologic changes in Dictyostelium and the...

RasC is required for optimal activation of adenylyl cyclase and Akt/PKB during aggregation

Lim, Chinten James, Spiegelman, George B., Weeks, Gerald

Disruption of Dictyostelium rasC, encoding a Ras subfamily protein, generated cells incapable of aggregation. While rasC expression is enriched in a cell type-specific manner during post-aggregative...

Control of Fatty Acid Metabolism I. Induction of the Enzymes of Fatty Acid Oxidation in Escherichia coli

Weeks, Gerald, Shapiro, Martin, Burns, R. O., Wakil, Salih J.

Escherichia coli grows on long-chain fatty acids after a distinct lag phase. Cells, preadapted to palmitate, grow immediately on fatty acids, indicating that fatty acid oxidation in this bacterium is...

Dictyostelium RasD is required for normal phototaxis, but not differentiation

Wilkins, Andrew, Khosla, Meenal, Fraser, Derek J., Spiegelman, George B., Fisher, Paul R., Weeks, Gerald, ...

RasD, a Dictyostelium homolog of mammalian Ras, is maximally expressed during the multicellular stage of development. Normal Dictyostelium aggregates are phototactic and thermotactic, moving towards...

RasC Plays a Role in Transduction of Temporal Gradient Information in the Cyclic-AMP Wave of Dictyostelium discoideum

Wessels, Deborah, Brincks, Rebecca, Kuhl, Spencer, Stepanovic, Vesna, Daniels, Karla J., Weeks, Gerald, ...

To define the role that RasC plays in motility and chemotaxis, the behavior of a rasC null mutant, rasC−, in buffer and in response to the individual spatial, temporal, and concentration components...

A Ras subfamily GTPase shows cell cycle-dependent nuclear localization

Sutherland, Brent W., Spiegelman, George B., Weeks, Gerald

Previously characterized Ras subfamily proteins have been found to be predominantly associated with the plasma membrane where they function in signal transduction pathways to convey extracellular...

Chemoattractant-induced Ras activation during Dictyostelium aggregation

Kae, Helmut, Lim, Chinten James, Spiegelman, George B, Weeks, Gerald

Ras proteins are highly conserved molecular switches that regulate cellular response to external stimuli. Dictyostelium discoideum contains an extensive family of Ras proteins that function in...

Delineation of the Roles Played by RasG and RasC in cAMP-dependent Signal Transduction during the Early Development of Dictyostelium discoideum

Bolourani, Parvin, Spiegelman, George B., Weeks, Gerald

On starvation, the cellular slime mold Dictyostelium discoideum initiates a program of development leading to formation of multicellular structures. The initial cell aggregation requires chemotaxis...

Rap1 controls cell adhesion and cell motility through the regulation of myosin II

Jeon, Taeck J., Lee, Dai-Jen, Merlot, Sylvain, Weeks, Gerald, Firtel, Richard A.

We have investigated the role of Rap1 in controlling chemotaxis and cell adhesion in Dictyostelium discoideum. Rap1 is activated rapidly in response to chemoattractant stimulation, and activated Rap1...

Cyclic AMP signalling in Dictyostelium: G-proteins activate separate Ras pathways using specific RasGEFs

Kae, Helmut, Kortholt, Arjan, Rehmann, Holger, Insall, Robert H, Spiegelman, George B, ...

In general, mammalian Ras guanine nucleotide exchange factors (RasGEFs) show little substrate specificity, although they are often thought to regulate specific pathways. Here, we provide in vitro and...

Dictyostelium RasG Is Required for Normal Motility and Cytokinesis, But Not Growth

Tuxworth, Richard I., Cheetham, Janet L., Machesky, Laura M., Spiegelmann, George B., Weeks, Gerald, Insall, Robert H.

RasG is the most abundant Ras protein in growing Dictyostelium cells and the closest relative of mammalian Ras proteins. We have generated null mutants in which expression of RasG is completely...

Regulation of Rap1 activity by RapGAP1 controls cell adhesion at the front of chemotaxing cells

Jeon, Taeck J., Lee, Dai-Jen, Lee, Susan, Weeks, Gerald, Firtel, Richard A.

Spatial and temporal regulation of Rap1 is required for proper myosin assembly and cell adhesion during cell migration in Dictyostelium discoideum. Here, we identify a Rap1 guanosine...

Regulation of Rap1 activity is required for differential adhesion, cell-type patterning and morphogenesis in Dictyostelium

Parkinson, Katie, Bolourani, Parvin, Traynor, David, Aldren, Nicola L., Kay, Robert R., Weeks, Gerald, ...

Regulated cell adhesion and motility have important roles during growth, development and tissue homeostasis. Consequently, great efforts have been made to identify genes that control these processes....