Over the past few years, a wealth of biochemical and functional data has been gathered on mammali... more Over the past few years, a wealth of biochemical and functional data has been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGMP kinase proteins generated by molecular biology techniques have yielded important biochemical knowledge, such as the function of the N-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, the substrate specificity of the enzymes and structural details of the catalytic center. Genetic approaches have proved to be especially useful for the analysis of the biological function of cGKs. Recently, some of the in vivo targets and mechanisms leading to smooth muscle relaxation have been identified. In vivo targets are the myosin-binding subunit of myosin phosphatase (PP1M), a member of the protein phosphatase 1, the calcium-activated maxi K(+) channel and a new protein named IRAG that forms a complex with the inositol 1,4,5-trisphosphate (...
Age‐dependent division of labour in honeybees was shown to be connected to sensory response thres... more Age‐dependent division of labour in honeybees was shown to be connected to sensory response thresholds. Foragers show a higher gustatory responsiveness than nurse bees. It is generally assumed that nutrition‐related signalling pathways underlie this behavioural plasticity. Here, one important candidate gene is the foraging gene, which encodes a cyclic guanosine monophosphate‐dependent protein kinase (PKG). Several roles of members of this enzyme family were analysed in vertebrates. They own functions in important processes such as growth, secretion and neuronal adaptation. Honeybee foraging messenger RNA expression is upregulated in the brain of foragers. In vivo activation of PKG can modulate gustatory responsiveness. We present for the first time PKG protein level and activity data in the context of social behaviour and feeding. Protein level was significantly higher in brains of foragers than in those of nurse bees, substantiating the role of PKG in behavioural plasticity. However, enzyme activity did not differ between behavioural roles. The mediation of feeding status appears independent of PKG signalling. Neither PKG content nor enzyme activity differed between starved and satiated individuals. We suggest that even though nutrition‐related pathways are surely involved in controlling behavioural plasticity, which involves changes in PKG signalling, mediation of satiety itself is independent of PKG.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 6, 2008
The cGMP/cGMP-dependent protein kinase I (cGKI) signaling pathway plays an important role in spin... more The cGMP/cGMP-dependent protein kinase I (cGKI) signaling pathway plays an important role in spinal nociceptive processing. However, downstream targets of cGKI in this context have not been identified to date. Using a yeast two-hybrid screen, we isolated cysteine-rich protein 2 (CRP2) as a novel cGKI interactor in the spinal cord. CRP2 is expressed in laminas I and II of the mouse spinal cord and is colocalized with cGKI, calcitonin gene-related peptide, and isolectin B4. Moreover, the majority of CRP2 mRNA-positive dorsal root ganglion (DRG) neurons express cGKI and peripherin. CRP2 is phosphorylated in a cGMP-dependent manner, and its expression increases in the spinal cord and in DRGs after noxious stimulation of a hindpaw. To elucidate the functional role of CRP2 in nociception, we analyzed mice with a targeted deletion of CRP2. CRP2-deficient (CRP2-/-) mice demonstrate normal behavioral responses to acute nociception and after axonal injury of the sciatic nerve, but increased n...
Over the past few years, a wealth of biochemical and functional data have been gathered on mammal... more Over the past few years, a wealth of biochemical and functional data have been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGK proteins generated by molecular biology techniques yielded important biochemical knowledge, such as the function of the NH2-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, and the substrate specificity of the enzymes. Genetic approaches have proven especially useful for the analysis of the biological functions of cGKs. Recently, some of the in vivo targets and mechanisms leading to changes in neuronal adaptation, smooth muscle relaxation and growth, intestinal water secretion, bone growth, renin secretion, and other important functions have been identified. These data show that cGKs are signaling molecules involved in many biological functions.
Smooth muscle expresses the Iα and the Iβ isoforms of cGMP-dependent protein kinase I (cGKI). Ina... more Smooth muscle expresses the Iα and the Iβ isoforms of cGMP-dependent protein kinase I (cGKI). Inactivation of the murine cGKI gene prkg1 leads to multiple phenotypes and premature death at ≈6 weeks. We reconstituted mice with the cGKIα or -Iβ isozyme to test which isozyme was needed to support basic smooth muscle functions. Mice were generated by gene targeting. The cGKIα or the -Iβ coding sequences were placed under the control of the SM22α promoter to express either isoform selectively in smooth muscle cells (SM-Iα or SM-Iβ transgene). To generate smooth muscle–specific cGKIα or cGKIβ rescue mice, the SM-Iα or SM-Iβ transgenes were crossed on a cGKI −/− genetic background. The levels of cGKIα or -Iβ expression were comparable to endogenous cGKI expression in wild-type aortic and intestinal smooth muscles. In cGKIα or -Iβ rescue mice, expression of the isozymes was not detectable in non–smooth muscle tissues and cells. Median survival time of the Iα and Iβ rescue mice was 52 weeks....
Defective regulation of platelet activation/aggregation is a predominant cause for arterial throm... more Defective regulation of platelet activation/aggregation is a predominant cause for arterial thrombosis, the major complication of atherosclerosis triggering myocardial infarction and stroke. A central regulatory pathway conveying inhibition of platelet activation/aggregation is nitric oxide (NO)/cyclic GMP (cGMP) signaling by cGMP-dependent protein kinase I (cGKI). However, the regulatory cascade downstream of cGKI mediating platelet inhibition is still unclear. Here, we show that the inositol-1,4,5-trisphosphate receptor–associated cGMP kinase substrate (IRAG) is abundantly expressed in platelets and assembled in a macrocomplex together with cGKIβ and the inositol-1,4,5-trisphosphate receptor type I (InsP3RI). cGKI phosphorylates IRAG at Ser664 and Ser677 in intact platelets. Targeted deletion of the IRAG-InsP3RI interaction in IRAGΔ12/Δ12 mutant mice leads to a loss of NO/cGMP-dependent inhibition of fibrinogen-receptor activation and platelet aggregation. Intracellular calcium tr...
Over the past few years, a wealth of biochemical and functional data has been gathered on mammali... more Over the past few years, a wealth of biochemical and functional data has been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGMP kinase proteins generated by molecular biology techniques have yielded important biochemical knowledge, such as the function of the N-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, the substrate specificity of the enzymes and structural details of the catalytic center. Genetic approaches have proved to be especially useful for the analysis of the biological function of cGKs. Recently, some of the in vivo targets and mechanisms leading to smooth muscle relaxation have been identified. In vivo targets are the myosin-binding subunit of myosin phosphatase (PP1M), a member of the protein phosphatase 1, the calcium-activated maxi K(+) channel and a new protein named IRAG that forms a complex with the inositol 1,4,5-trisphosphate (...
Age‐dependent division of labour in honeybees was shown to be connected to sensory response thres... more Age‐dependent division of labour in honeybees was shown to be connected to sensory response thresholds. Foragers show a higher gustatory responsiveness than nurse bees. It is generally assumed that nutrition‐related signalling pathways underlie this behavioural plasticity. Here, one important candidate gene is the foraging gene, which encodes a cyclic guanosine monophosphate‐dependent protein kinase (PKG). Several roles of members of this enzyme family were analysed in vertebrates. They own functions in important processes such as growth, secretion and neuronal adaptation. Honeybee foraging messenger RNA expression is upregulated in the brain of foragers. In vivo activation of PKG can modulate gustatory responsiveness. We present for the first time PKG protein level and activity data in the context of social behaviour and feeding. Protein level was significantly higher in brains of foragers than in those of nurse bees, substantiating the role of PKG in behavioural plasticity. However, enzyme activity did not differ between behavioural roles. The mediation of feeding status appears independent of PKG signalling. Neither PKG content nor enzyme activity differed between starved and satiated individuals. We suggest that even though nutrition‐related pathways are surely involved in controlling behavioural plasticity, which involves changes in PKG signalling, mediation of satiety itself is independent of PKG.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 6, 2008
The cGMP/cGMP-dependent protein kinase I (cGKI) signaling pathway plays an important role in spin... more The cGMP/cGMP-dependent protein kinase I (cGKI) signaling pathway plays an important role in spinal nociceptive processing. However, downstream targets of cGKI in this context have not been identified to date. Using a yeast two-hybrid screen, we isolated cysteine-rich protein 2 (CRP2) as a novel cGKI interactor in the spinal cord. CRP2 is expressed in laminas I and II of the mouse spinal cord and is colocalized with cGKI, calcitonin gene-related peptide, and isolectin B4. Moreover, the majority of CRP2 mRNA-positive dorsal root ganglion (DRG) neurons express cGKI and peripherin. CRP2 is phosphorylated in a cGMP-dependent manner, and its expression increases in the spinal cord and in DRGs after noxious stimulation of a hindpaw. To elucidate the functional role of CRP2 in nociception, we analyzed mice with a targeted deletion of CRP2. CRP2-deficient (CRP2-/-) mice demonstrate normal behavioral responses to acute nociception and after axonal injury of the sciatic nerve, but increased n...
Over the past few years, a wealth of biochemical and functional data have been gathered on mammal... more Over the past few years, a wealth of biochemical and functional data have been gathered on mammalian cGMP-dependent protein kinases (cGKs). In mammals, three different kinases are encoded by two genes. Mutant and chimeric cGK proteins generated by molecular biology techniques yielded important biochemical knowledge, such as the function of the NH2-terminal domains of cGKI and cGKII, the identity of the cGMP-binding sites of cGKI, and the substrate specificity of the enzymes. Genetic approaches have proven especially useful for the analysis of the biological functions of cGKs. Recently, some of the in vivo targets and mechanisms leading to changes in neuronal adaptation, smooth muscle relaxation and growth, intestinal water secretion, bone growth, renin secretion, and other important functions have been identified. These data show that cGKs are signaling molecules involved in many biological functions.
Smooth muscle expresses the Iα and the Iβ isoforms of cGMP-dependent protein kinase I (cGKI). Ina... more Smooth muscle expresses the Iα and the Iβ isoforms of cGMP-dependent protein kinase I (cGKI). Inactivation of the murine cGKI gene prkg1 leads to multiple phenotypes and premature death at ≈6 weeks. We reconstituted mice with the cGKIα or -Iβ isozyme to test which isozyme was needed to support basic smooth muscle functions. Mice were generated by gene targeting. The cGKIα or the -Iβ coding sequences were placed under the control of the SM22α promoter to express either isoform selectively in smooth muscle cells (SM-Iα or SM-Iβ transgene). To generate smooth muscle–specific cGKIα or cGKIβ rescue mice, the SM-Iα or SM-Iβ transgenes were crossed on a cGKI −/− genetic background. The levels of cGKIα or -Iβ expression were comparable to endogenous cGKI expression in wild-type aortic and intestinal smooth muscles. In cGKIα or -Iβ rescue mice, expression of the isozymes was not detectable in non–smooth muscle tissues and cells. Median survival time of the Iα and Iβ rescue mice was 52 weeks....
Defective regulation of platelet activation/aggregation is a predominant cause for arterial throm... more Defective regulation of platelet activation/aggregation is a predominant cause for arterial thrombosis, the major complication of atherosclerosis triggering myocardial infarction and stroke. A central regulatory pathway conveying inhibition of platelet activation/aggregation is nitric oxide (NO)/cyclic GMP (cGMP) signaling by cGMP-dependent protein kinase I (cGKI). However, the regulatory cascade downstream of cGKI mediating platelet inhibition is still unclear. Here, we show that the inositol-1,4,5-trisphosphate receptor–associated cGMP kinase substrate (IRAG) is abundantly expressed in platelets and assembled in a macrocomplex together with cGKIβ and the inositol-1,4,5-trisphosphate receptor type I (InsP3RI). cGKI phosphorylates IRAG at Ser664 and Ser677 in intact platelets. Targeted deletion of the IRAG-InsP3RI interaction in IRAGΔ12/Δ12 mutant mice leads to a loss of NO/cGMP-dependent inhibition of fibrinogen-receptor activation and platelet aggregation. Intracellular calcium tr...
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Papers by J. Schlossmann