Romi Valkema

Phosphorylation of Chemoattractant Receptors Is Not Essential for Chemotaxis or Termination of G-protein-mediated Responses (1997)

Kim, Ji-Yun, Soede, Ron D.M., Schaap, Pauline, Valkema, Romi, Borleis, Jane A., Haastert, Peter J.M. Van, ...

In several G-protein-coupled signaling systems, ligand-induced receptor phosphorylation by specific kinases is suggested to lead to desensitization via mechanisms including receptor/G-protein...

The G Protein β Subunit Is Essential for Multiple Responses to Chemoattractants in Dictyostelium (1995)

Wu, Lijun, Valkema, Romi, Haastert, Peter J.M. Van, Devreotes, Peter N.

Increasing evidence suggests that the βγ-subunit dimers of heterotrimeric G proteins play a pivotal role in transducing extracellular signals. The recent construction of Gβ null mutants (gβ-) in...

A Model for cAMP-mediated cGMP Response in Dictyostelium discoideum (1994)

Valkema, Romi, Haastert, Peter J.M. Van

In Dictyostelium discoideum extracellular cyclic AMP (cAMP), as shown by previous studies, induces a transient accumulation of intracellular cyclic guanosine-5'-monophosphate (cGMP), which peaks at...

Inhibition of Receptor-Stimulated Guanylyl Cyclase by Intracellular Calcium Ions in Dictyostelium Cells (1992)

Valkema, Romi, Haastert, Peter J.M. Van

In Dictyostelium discoideum extracellular cAMP stimulates guanylyl cyclase and phospholipase C; the latter enzyme produces Ins(1,4,5)P3 which releases Ca2+ from internal stores. The following data...