Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When sea urchin spermatozoa were treated with a Triton X-100 solution, cAMP-dependent protein kinase (cA-kinase) activity was extracted. Further extraction with Triton X-100 of axonemes isolated from the Triton-extracted sperm again released a considerable amount of the cA-kinase activity. The activity which remained after extraction three times with Triton X-100 was released by treatment with a low salt solution. These activities found in the various extracts were likely to be due to the same cA-kinase, which was a mammalian type II-like enzyme. The cA-kinase activity that remained in the axonemes after the first Triton X-100 extraction may be involved in the regulation of flagellar movement in the Triton-extracted sperm.
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PMID:The cAMP-dependent protein kinase in sea urchin sperm tails: association of the enzyme with the flagellar axonemes. 222 2

Highly purified plasma membranes (PMs) isolated by aqueous two-phase polymer methods from goat sperm undergoing epididymal maturation, have been analyzed for the isoenzymes of cyclic AMP-dependent protein kinase (RC). The mature and the immature spermatozoa showed profound differences in the profile of the isoenzymes of RC solubilized from the isolated PMs with 0.1% Triton X-100. The immature sperm PM consists of only type I RC in contrast to the mature sperm membrane which possesses both the type I and II isoenzymes. The type II kinase represents nearly 30% of the total membrane-bound RC of the mature cells. The analysis of the surface topography of these isoenzymes of the maturing spermatozoa by using diazonium salt of sulfanilic acid as the surface probe shows that the PM-bound RC(s) are oriented primarily on the external surface of these intact cells. The data demonstrate that type II RC is a maturation-specific ecto-kinase as it appears on the sperm surface specifically during the maturation of spermatozoa in the epididymis.
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PMID:Maturation-specific type II cyclic AMP-dependent protein kinase in goat sperm plasma membrane. 224 92

We used two different anti-phosphotyrosine antibodies to identify phosphotyrosine-containing proteins in a germ cell, the boar spermatozoon. Ejaculated spermatozoa presented three major polypeptides, of Mr 43,000, 40,000 and 36,000, respectively, that were immunorecognized on Western blots. These proteins were selectively enriched in the Triton X-100-soluble fraction and were released neither after an A23187-induced acrosome reaction nor after sperm homogenization. These findings suggest the presence of the three proteins in plasma membrane regions not involved in the acrosomal vesiculation. When epididymal boar spermatozoa were investigated, Western blot analysis of the detergent-soluble fractions from caput sperm did not reveal any detectable 43,000, 40,000 and 36,000 Mr proteins cross-reactive with phosphotyrosine antibodies, whereas the detergent-soluble fractions from cauda sperm yielded very strong immunoreactive signals. Labelling of freshly ejaculated spermatozoa with [32P]orthophosphate yielded a wide range of labelled phosphoproteins, but we failed to identify specific tyrosine phosphorylation under the experimental conditions employed. Tyrosine phosphorylation occurred when specific synthetic polymers of tyrosine, commonly used for studying tyrosine protein kinases, were assayed as substrates against both the Triton-soluble and Triton-insoluble sperm fractions. This is the first immunological and biochemical report on the presence of phosphotyrosine-containing proteins and protein kinase activities that phosphorylate tyrosine residues in a mammalian mature spermatozoon.
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PMID:Identification of proteins cross-reactive to phosphotyrosine antibodies and of a tyrosine kinase activity in boar spermatozoa. 248 84

Cholesteryl ester hydrolase (CEH) was measured at 32 degrees C and 37 degrees C, and with and without cofactors for stimulation of cyclic AMP-dependent protein kinase, in 104,000 X g supernatants from rats aged 14-365 days. Activity at the two temperatures was also partially resolved by cation exchange FPLC. Total specific activity of CEH was relatively constant, with or without addition of cofactors, from 14 to 47 days, during which time temperature labile CEH was a very small fraction of total CEH activity. At later times, 51-150 days, activity was increased as much as two-fold, both with and without cofactors, with most of the increase occurring in the temperature labile fraction. Activation of temperature stable and temperature labile activities, where present, by protein kinase cofactors could be demonstrated in all age groups, but was highly variable as a function of age and protein concentration used in the assay. Apparent induction of temperature labile activity over the interval 47-51 days coincides with reported increases in testosterone synthesis and first appearance of spermatozoa in the testis. This and other lines of evidence suggest unique roles for these enzymes in regulation of availability of free cholesterol for testosterone and membrane synthesis, respectively.
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PMID:Temperature lability and cAMP-dependent protein kinase activation of cholesteryl ester hydrolase as a function of age in developing rat testis. 258 39

There is substantial evidence that cAMP-dependent phosphorylation is involved in the activation of motility of spermatozoa as they are released from storage in the male reproductive tract. This evidence includes observations that in vivo activation of motility can be inhibited by protein kinase inhibitors, can be reversed by protein phosphatase treatment of demembranated spermatozoa, and is associated with phosphorylation of sperm proteins, and observations that spermatozoa that have not been activated in vivo can be activated in vitro by cAMP-dependent phosphorylation. Activation in vivo can often be triggered by conditions that increase intracellular pH, but the relevance of this to in vivo activation under natural conditions and the steps between pH increase and cAMP increase have not been fully established. The relationships between changes in the protein substrates for cAMP-dependent phosphorylation and changes in axonemal function are still unknown. Sperm chemotaxis to egg secretions is widespread; in the sea urchin Arbacia, the egg jelly peptide resact has been identified as a chemoattractant. Response to chemoattractants involves changes in asymmetry of flagellar bending waves, and similar changes in asymmetry can be produced in vitro by increases in [Ca++]. Temporal changes in resact receptor occupancy might lead to transient changes in intracellular [Ca++] and the asymmetry of flagellar bending, but many links in this hypothetical sequence remain to be established. Both of these signalling systems offer immediate opportunities for investigations of biochemical pathways leading to easily assayable biological responses. However, complications resulting from interactions between these two systems need to be considered.
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PMID:Regulation of sperm flagellar motility by calcium and cAMP-dependent phosphorylation. 282 4

Mammalian spermatozoa have been shown to possess cAMP-dependent protein kinase (A-PK) and endogenous substrate proteins for this enzyme. A study of the kinase system was undertaken to determine changes that may be associated with sperm maturation by comparing immature testicular with mature cauda epididymal and ejaculated spermatozoa. Absolute activity levels of A-PK, stimulated over a concentration range of 10(-9) to 10(-5) M, was significantly greater in testicular than ejaculated spermatozoa. At an optimal cAMP concentration (10(-6) M), testicular spermatozoa had significantly greater amounts of cAMP-dependent protein kinase activity than did cauda or ejaculated spermatozoa. Electrophoretic analysis and autoradiography of NP-40-soluble protein extracts revealed the presence of two substrate proteins (Mr = 62,000 and 44,000) in all three types of spermatozoa. In addition, a phosphoprotein (Mr = 20,000) was detected in mature cauda and ejaculated but not immature testicular spermatozoa. The phosphorylation of these substrate proteins was both dose and time dependent. Examination of cyclic AMP phosphodiesterase activity revealed significantly higher levels in testicular than ejaculated spermatozoa. These results indicate marked alterations in cAMP-modulated protein phosphorylation and dephosphorylation systems in ram spermatozoa during epididymal maturation.
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PMID:Characterization of cAMP-dependent protein kinase and its endogenous substrate proteins in ram testicular, cauda epididymal, and ejaculated spermatozoa. 285 34

Guanylate cyclase has been strongly implicated as a cell-surface receptor on spermatozoa for a chemotactic peptide, and on various other cells as a receptor for atrial natriuretic peptides. Resact (Cys-Val-Thr-Gly-Ala-Pro-Gly-Cys-Val-Gly-Gly-Gly-Arg-Leu-NH2), the chemotactic peptide released by sea urchin Arbacia punctulata eggs, is specifically crosslinked to A. punctulata spermatozoan guanylate cyclase. After the binding of the peptide the state of guanylate cyclase phosphorylation modulates enzyme activity. We report here that the deduced amino-acid sequence of the spermatozoan membrane form of guanylate cyclase predicts an intrinsic membrane protein of 986 amino acids with an amino-terminal signal sequence. A single transmembrane domain separates the protein into putative extracellular and cytoplasmic-catalytic domains. The cytoplasmic carboxyl-terminal 95 amino acids contain 20% serine, the likely regulatory sites for phosphorylation. Unexpectedly, the enzyme is homologous to the protein kinase family.
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PMID:Membrane guanylate cyclase is a cell-surface receptor with homology to protein kinases. 290 Oct 39

Calmodulin concentration and cAMP-dependent protein kinase activity were simultaneously determined on ram spermatozoa collected by cannulation of successive segments of the epididymal tubule. Epididymal transit was characterized on one hand by an overall decrease in the calmodulin level and on the other by a dramatic rise in the cAMP-dependent protein kinase activity. In contrast to the calmodulin level, the cAMP-dependent protein kinase activity was correlated with the acquisition of flagellar beat. No further alterations in the level of these two proteins could be detected as spermatozoa acquired progressive motility.
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PMID:Changes in calmodulin level and cAMP-dependent protein kinase activity during epididymal maturation of ram spermatozoa. 299 10

An intact organelle, the prostasome, is secreted by the acinar epithelial cell of the human prostate gland. The ultrastructural location of the prostasome is within membrane-bound storage vesicles in the epithelial cells. Prostasomes are delivered into the glandular lumen by an exocytotic event, which is preceded by fusion of adjacent membranes belonging to the storage vesicle and the epithelial cell. Alternatively, the storage vesicle can be translocated in toto from the cell interior into the acinar lumen through the plasma membrane. This latter event has been designated diacytosis. Both phenomena seem to occur with approximately equal frequency in the human prostate gland. An ATPase system that is Mg2+ and Ca2+-dependent is firmly linked to the membranes encasing the prostasomes. The ATPase system may be the molecular basis for vectorial transport of calcium into these organelles. Also a protein kinase activity is located in the membranes. An increase in membrane thickness was observed on phosphorylation. The physiologic function of the prostasomes is not known. They may be important for promoting forward motility of spermatozoa.
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PMID:The prostasome: its secretion and function in man. 299 93

8-Azido cAMP photoaffinity labeling of cAMP-dependent protein kinase regulatory subunits (R1 = 49 K;R2 = 55K) was done on spermatozoa from species lacking, and species containing an epididymis. Spermatozoa from sea urchin and trout contained only R1, while rat caudaepididymal spermatozoa contained both R1 and R2 subunits. This was established by the Mr value of the 8-azido cAMP photolabeled moieties, and a biochemical analysis based on the known differences of protein-nucleotide interactions of Type I and II cAMP-dependent protein kinases. Sea urchin and trout sperm R1 subunits were similar to mammalian sperm R1 subunits in co-migration on SDS-polyacrylamide gels and in both saturation and specificity of nucleotide binding. Calcium enhanced photoprobe binding to rat R1 and R2 subunits and to sea urchin R1 subunit without revealing a sea urchin R2 subunit. Likewise, phosphodiesterase incubation of sea urchin and trout spermatozoa prior to photolabeling did not reveal R2 subunits. These data suggest that the cAMP regulation of sperm physiology may require R1 subunit in species both with and without an epididymis. Further taxonomic study is necessary to determine whether evolutionary acquisition of the epididymis and internal fertilization may have created unique environments favoring the addition of sperm R2 regulatory subunits of cAMP-dependent protein kinase.
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PMID:A comparative analysis of cAMP-dependent protein kinase regulatory subunits in sea urchin and rat spermatozoa. 299 17


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