Guanosine monophosphate kinase

ATP GMP phosphotransferase GMP kinase deoxyguanylate kinase guanosine monophosphate kinase kinase, guanylate (phosphorylating)... 

The ANP leceptoi exists in two forms, ANP and ANPg, both of which have been cloned. These membrane-bound guanylate cyclases have a single transmembrane domain, an intracellular protein kinase-like domain, and a catalytic cyclase domain, activation of which results in the accumulation of cychc guanosine monophosphate (cGMP). A third receptor subtype (ANP ) has been identified that does not have intrinsic guanylate cyclase activity and may play a role in the clearance of ANP. 

The antiviral mechanism of action of acyclovir has been reviewed (72). Acyclovir is converted to the monophosphate in herpes vims-infected cells (but only to a limited extent in uninfected cells) by viral-induced thymidine kinase. It is then further phosphorylated by host cell guanosine monophosphate (GMP) kinase to acyclovir diphosphate [66341 -17-1], which in turn is phosphorylated to the triphosphate by unidentified cellular en2ymes. Acyclovir triphosphate [66341 -18-2] inhibits HSV-1 viral DNA polymerase but not cellular DNA polymerase. As a result, acyclovir is 300 to 3000 times more toxic to herpes vimses in an HSV-infected cell than to the cell itself. Studies have shown that a once-daily dose of acyclovir is effective in prevention of recurrent HSV-2 genital herpes (1). HCMV, on the other hand, is relatively uninhibited by acyclovir. 

Cyclic-AMP Response Element Binding Protein Cyclic GMP-dependent Protein Kinase Cyclic GMP-regulated Phosphodiesterases Cyclic Guanosine Monophosphate (Cyclic GMP cGMP)... 

Massberg S, Sausbier M, Klatt P et al. (1999) Increased adhesion and aggregation of platelets lacking cyclic guanosine 3, 5 -monophosphate kinase I. J Exp Med 189 1255-1264... 

CDK2, cell division kinase 2 cDNA, complementary DNA CDP, cytidine 5 -diphosphate CDPK, Ca2+-dependent protein kinase, calmodulin domain protein kinase CFTR, cystic fibrosis transmembrane conductance regulator cGMP, 3, 5 -c.yclic guanosine monophosphate cGMP PDE, cyclic GMP phosphodiesterase... 

Some biosynthetic reactions are driven by the hydrolysis of nucleoside triphosphates that are analogous to ATP—namely, guanosine triphosphate (GTl ), uridine triphosphate (UTP), and cytidine triphosphate (CTP). The diphosphate forms of these nucleotides are denoted by GDP, UDP, and CDP, and the monophosphate forms are denoted by GMP, UMP, and CMP. Enzymes catalyze the transfer of the terminal phosphoryl group from one nucleotide to another. The phosphorylation of nucleoside monophosphates is catalyzed by a family of nucleoside monophosphate kinases, as discussed in Section 9.4. The phosphorylation of nucleoside diphosphates is catalyzed by 7iucleoside diphosphate kinase, an enzyme with broad... 

Fig. 30. A. Frontal section through the cerebellum and attached brainstem of an adult rat. All the Purkinje cells are stained by cyclic 3, 5 -guanosine monophosphate-dependent protein kinase (cGK) antiserum, including their dendrites in the molecular layer and their axon terminals in the deep nuclei and in the brainstem (arrow). Bar = 1 mm. B. Higher magnification of the neurons indicated by an arrow head in A. Like a few other isolated labelled cells found in variable locations, these cells are considered as ectopic Purkinje cells. Bar = 50 /tm. C. cGK immunoreactive neuron in the cerebellum of I day-old rat. This ectopic Purkinje cell is located in the white matter and its appearance mimics that of 1-day-old Purkinje cells as visualized in Golgi impregnated material. Bar = 25 /tm. Wassef and Sotelo (1984).

Fig. 155. Staining with cyclic 3, 5 -guanosine monophosphate dependent protein kinase (cGK) antisera of sections of cerebellum of rat fetuses of embryonic day E17, E19 and a neonate (PO) cut in the frontal plane. A,B- E17. Cluster I is composed of a medial sheet (arrow in B) lying against the germinative neuroepithelium. Close to the midline this sheet bends dorsally and reaches the cortex. The central cluster (CC) is located at the center of the hemicerebellum. C. E19. In this section four of the five cGK-positive clusters I-V are present. The labelled fiber-like material, which tails the labelled clusters ( and o) indicates the migration pathways followed by the Purkinje cells of the clusters I and III from the subventricular plate and the central cluster at El7 to their present, superficial position. D. PO rat pup. Fiber bundles linking the clusters I and III with the cerebellar nuclei intersect at the former position of the central cluster. It is suggested that the bundle from cluster III ( ) terminates in the dorsolateral protuberance. In the adult this connection corresponds to the projection of the lateral extension of the A zone of Buisseret-Delmas (1988a, compare Figs. 142 and 144). Bar in A = 100 /tm, in B, C and D = 500 fxm. Wassef and Sotelo (1984).

For the receptors that bind atrial natriuretic peptides and the peptides guanylin and uroguanylin, the intracellular domain is not a protein kinase but rather a guanylyl cyclase that synthesizes the second messenger cyclic guanosine monophosphate (cyclic GMP), which activates a cyclic GMP-dependent protein kinase (PKG) and can modulate the activities of several cyclic nucleotide phosphodiesterases, among other effectors. 

Second messengers are specific intracellular components that are indirectly stimulated by the first messengers to activate intracellular components such as certain enzymes termed protein kinases (PKs). The most studied second messengers are calcium ion, inositol trisphosphate (IP3), diacylglycerol (DAG), cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). 

Figure 3. Compartmentalization of the purine salvage pathway of Leishmania. Abbreviations are as follows AAH, adenine aminohydrolase XPRT, xanthine phosphoribosyltransferase HGPRT, hypoxanthine-guaninephosphoribosyltransferase ADSS, adenylosuccinate synthetase ASL, adenylosuccinate lyase IMPDH, inosine monophosphate dehydrogenase GMPS, gua-nosine monophosphate synthase GDA, guanine deaminase AMPDA, adenosine monophosphate deaminase GMPR, guanosine monophosphate reductase APRT, adenine phosphoribosyltransferase AK, adenosine kinase. Enzymes that have been localized are shown in black and those that are predicted to be in the denoted locations are depicted in gray.

---