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)

Protein kinase activities in seminal fluids of normo-, hypo-, and oligozoospermic and vasectomized men were measured using lysine-rich histones and partially dephosphorylated phosvitin as acceptor substrates. There was a significant relationship of histone kinase but not phosvitin kinase activities with the number of spermatozoa originally present in the semen. Histone kinase and phosvitin kinase activities were diminished 88% and 62%, respectively, in vasectomy seminal fluid. The sex accessory gland sources of seminal fluid protein kinase activities not associated with spermatozoa were examined in split ejaculates of vasectomized men. Histone kinase activity was greater in the first fractions, suggesting that the prostate is its predominant contributor; whereas the distribution of phosvitin kinase activity did not indicate any preferential accessory gland source of this enzyme.
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PMID:Tissue sources of protein kinase activities in human seminal fluid: studies of normal, oligozoospermic, and vasectomized men. 686 38

Protein kinase activity (EC 2.7.1.37) of buffalo spermatozoa is distributed in the head (22%) and midpieces + tails (74%). Extraction of sperm heads with 0.1% Triton X-100 solubilized 35--40 of the protein kinase activity and the remaining 60--65% was associated tightly with the sperm chromatin. That the sperm chromatin preparation was pure was established by recording its spectrum at 320/260 nm (0.07), determining its composition (protein:DNA ratio, 0.79), electron microscope examination and through the assay of marker enzymes. Extraction of the chromatin preparation with 1 M-NaCl only partly solubilized the protein kinase activity while treatment with DNase in the presence of dithiothreitol inactivated the nuclear protein kinase. The chromatin-associated protein kinase activity had a broad pH optimum (7.6--8.4), an essential requirement for Mg2+ and ATP as a phosphate donor. Histones and non-histone proteins served as substrates, the preferred substrate being arginine rich histone VIII followed by casein and phosvitin. Nuclear protein kinase activity was neither stimulated by cyclic AMP nor inhibited by purified muscle protein kinase inhibitor. It is suggested that chromatin-associated protein kinase (Type III protein kinase) may be involved in the control of DNA-template activity.
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PMID:Association of buffalo sperm protein kinase with sperm chromatin. 712 Jan 98

In nuclei and nucleoli of the slime mold Physarum polycephalum, ornithine decarboxylase (OrnDCase) (Mr 70,000) is phosphorylated by a protein kinase reaction that is dependent on spermidine and spermine. Putrescine antagonizes the phosphorylation. Phosphorylation of OrnDCase inhibits its capacity to catalyze decarboxylation of ornithine. The protein kinase that catalyzes this phosphorylation has many properties similar to those of nuclear protein kinase II, or type G, which has been studied by other groups. The interaction of this protein kinase with OrnDCase resembles the behavior of the OrnDCase antizyme described by other investigators. Phosphorylated OrnDCase binds to purified, palindromic rDNA isolated from nucleoli. It also stimulates transcription of the ribosomal genes by RNA polymerase I in a chromatin form of rDNA. It does not stimulate transcription in a purified, homologous transcription system comprised of RNA polymerase I, rDNA, and phospho-OrnDCase. Thus, phospho-OrnDCase may have a function in promoting rRNA gene transcription but the detailed mechanism is yet unclear. The polyamine-dependent protein kinase and its natural substrate of 70,000 daltons have been demonstrated in other eukaryotic cells, including bovine spermatozoa and rat liver nuclei, and in Ehrlich ascites tumor cells, where the protein kinase is induced by interferon. This phosphorylation system appears to be widely distributed and conserved among eukaryotic species.
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PMID:Posttranslational control of ornithine decarboxylase by polyamine-dependent protein kinase. 714 Oct 3

This study provides evidence for the occurrence of a biochemical function for the polyamines, spermidine and spermine, in bovine epididymal spermatozoa. Methods are described for the detection and isolation of a protein kinase from spermatozoa which catalyzed transfer of phosphate from [gamma-32P]ATP to a unique endogenous protein of Mr = 70,000 in a reaction that was polyamine-dependent. Enzymatic phosphorylation of the 70,000-dalton protein by the purified protein kinase was sharply activated, at times more than 80-fold, by the polyamines, spermidine and spermine. Spermidine and spermine, together in equimolar combination, synergistically activated the protein kinase when compared with all other possible combinations of putrescine, spermidine, or spermine. The polyamine-dependent protein kinase was resolved by phosphocellulose chromatography into a catalytic component of Mr = 19,000 and a complex comprised of the catalytic component associated with the natural phosphate-acceptor protein of Mr = 70,000. This protein kinase was not activated by cyclic nucleotides or calcium ion.
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PMID:A polyamine-dependent protein kinase from bovine epididymal spermatozoa. 726 52

Phosphorylation of demembranated fowl sperm proteins during incubation with [gamma-32P]ATP and various protein kinase substrate peptides at 30 degrees C was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A marked difference in phosphorylation was observed in a 30 kDa protein. This protein was strongly phosphorylated after the addition of Kemptide, a cAMP-dependent protein kinase (PKA) substrate peptide; Syntide 2, a calmodulin-dependent protein kinase II substrate peptide; a protein kinase C (PKC) substrate peptide; as well as control samples but only slightly phosphorylated in the presence of a myosin light chain kinase (MLCK) substrate peptide. The motility of demembranated spermatozoa at 30 degrees C remained high in control samples and following the addition of Kemptide, Syntide 2 and PKC substrate peptide, but decreased markedly following the addition of MLCK substrate peptide. These results suggest that the 30 kDa protein is identified as a substrate for MLCK or a MLCK-like protein in fowl spermatozoa and that phosphorylation-dephosphorylation of this protein is involved in the regulation of flagellar movement at 30 degrees C.
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PMID:Dephosphorylation of a 30-kDa protein of fowl spermatozoa by the addition of myosin light chain kinase substrate peptide inhibits the flagellar motility. 748 12

In mammalian spermatozoa, most of the type II alpha isoform of cAMP-dependent protein kinase (PKAII alpha) is anchored at the cytoplasmic surface of a specialized array of mitochondria in the flagellar cytoskeleton. This places the catalytic subunits of PKAII alpha in proximity with potential target substrates in the cytoskeleton. The mechanism by which PKAII alpha is anchored at the outer surface of germ cell mitochondria has not been elucidated. We now report the cloning of a cDNA that encodes a novel, germ cell A kinase anchor protein (AKAP) designated S-AKAP84. S-AKAP84 comprises 593 amino acids and contains a centrally located domain that avidly binds regulatory subunits (RII alpha and RII beta) of PKAII alpha and PKAII beta. The 3.2-kilobase S-AKAP84 mRNA and the cognate S-AKAP84 RII binding protein are expressed principally in the male germ cell lineage. Expression of S-AKAP84 is tightly regulated during development. The protein accumulates as spermatids undergo nuclear condensation and tail elongation. The timing of S-AKAP84 expression is correlated with the de novo accumulation of RII alpha and RII beta subunits and the migration of mitochondria from the cytoplasm (round spermatids) to the cytoskeleton (midpiece in elongating spermatids). Residues 1-30 at the NH2 terminus of S-AKAP84 constitute a putative signal/anchor sequence that may target the protein to the outer mitochondrial membrane. Immunofluorescence analysis demonstrated that S-AKAP84 is co-localized with mitochondria in the flagellum.
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PMID:Characterization of S-AKAP84, a novel developmentally regulated A kinase anchor protein of male germ cells. 749 50

The interaction of the mammalian spermatozoon with the oocyte's extracellular matrix or zona pellucida is a critical first step leading to successful fertilization. In this cell-extracellular matrix interaction it is the carbohydrate of the zona pellucida which serves as the sperm receptor and the surface of the spermatozoon which provides the lectin-like adhesion molecules. To better understand sperm-zona pellucida binding we have analyzed one specific zona binding protein (ZBP). This study has determined the mRNA sequence encoding a mammalian testis and sperm specific protein of 16,891 Da, which we have designated Sp17. Analysis of Sp17 revealed that the mRNA is present in rabbit, mouse, and human testes but not in any somatic tissue tested. In the rabbit, Sp17 is the 17-kDa member of the rabbit sperm autoantigen family of sperm specific autoantigens and is encoded by two mRNAs of 0.9 and 1.1 kb. Each mRNA has a unique 5' untranslated region but both have identical coding regions. The deduced amino acid sequence of the Sp17 ZBP showed several interesting features, including a similarity to the N-terminal of human testis cAMP-dependent protein kinase. Localization of Sp17 on live spermatozoa using antibodies to recombinant Sp17 or to the Sp17 peptide, G22C, revealed that the peptide backbone of Sp17 is inaccessible until the acrosome reaction begins. However, on paraformaldehyde fixed, acrosome intact spermatozoa, the peptide backbone is accessible to the antibodies which localize Sp17 to the apical surface. In the rabbit as well as other similar species in which the corona radiata (granulosa) cells adhere tightly to the zona pellucida and synthesize zona glycoproteins, the fertilizing spermatozoon may have already begun the acrosome reaction within the cumulus oophorus. Thus, the rabbit sperm surface would be modified to expose the Sp17 polypeptide during the final phase of cumulus passage and consequently Sp17 would be available for initial zona binding. The present study has also demonstrated that recombinant Sp17 can bind zona pellucida, dextran, and dextran sulfate.
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PMID:Sequence of a rabbit sperm zona pellucida binding protein and localization during the acrosome reaction. 752 87

The motility of both intact and demembranated fowl spermatozoa was vigorous at 30 degrees C, but decreased markedly following the addition of 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-9), a specific inhibitor of myosin light chain kinase (MLCK). Furthermore, the presence of a MLCK substrate peptide also inhibited the motility of demembranated spermatozoa at 30 degrees C. In contrast, the addition of N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-8) or N-(2-guanidinoethyl)-5-isoquinolinesulfonamide dihydrochloride (HA1004), specific inhibitors of cAMP-dependent protein kinase, did not appreciably affect the motility of either intact or demembranated spermatozoa. Cyclic AMP-dependent protein kinase substrate peptides were also ineffective for the inhibition of motility of demembranated spermatozoa at 30 degrees C. Immunoblotting of sperm extract, using an antibody to MLCK, revealed two major crossreacting proteins of 130 kDa and 61-64 kDa, which corresponded to the molecular mass of MLCK. In addition, immunogold particles, which reacted with the anti-MLCK antibody, were observed around or on the axoneme at the ultrastructural level. These results suggest that the phosphorylation of axonemal protein(s) by MLCK, or a MLCK-like protein, rather than by cAMP-dependent protein kinase, may be involved in the maintenance of fowl sperm motility at 30 degrees C.
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PMID:Regulatory mechanisms of fowl sperm motility: possible role of endogenous myosin light chain kinase-like protein. 763 95

The human sperm acrosome reaction (AR) occurs via the activation of at least two signal transduction pathways. The purpose of this investigation was to characterize two of the pathways, the protein kinase A (PKA) and C (PKC) pathways, and determine whether pathway "crosstalk" occurs between them in eliciting the AR in capacitated spermatozoa. Stimulators of each pathway were tested in a dose-dependent manner. ARmax, ED50, and delta ARmax (%ARmax-%ARcontrol) values were calculated. The PKA pathway stimulators forskolin and dibutyryl cyclic AMP (dbcAMP) induced an ARmax at 1.0 microM and 1.0 mM, respectively. The ED50 and delta ARmax values were: 0.01 microM and 17% for forskolin and 0.069 mM and 13% for dbcAMP. Two stimulator types of the PKC pathway were tested: synthetic diacylglycerols (DG) and a phorbol diester. 1,2-dioleoyl-sn-glycerol and 1,2-dioctanoyl-sn-glycerol, analogues of the PKC-activating second messenger DG, each induced an ARmax at 50 microM. The ED50 and delta AR max values were: 33 microM and 24% for 1,2-dioleoyl and 34.8 microM and 34% for 1,2-dioctanoyl. 4 beta-Phorbol-12,13-didecanoate, a PKC stimulator, induced an ARmax at 0.1 microM. The ED50 and delta ARmax were 0.021 microM and 26%. An inhibitor of each kinase was added at the end of the capacitation period and prior to stimulation by inducers at their ARmax dose. KT5720, a PKA inhibitor, caused a dose-dependent reduction of the forskolin and dbcAMP-induced AR. Calphostin C, a PKC inhibitor, prevented stimulation of the AR by 1,2-dioleoyl and 4 beta-phorbol-12,13-didecanoate. To investigate pathway "crosstalk," the following experiments were conducted: (1) stimulators of each pathway were combined and tested at the ARmax and ED50 concentrations for each; (2) spermatozoa were pretreated with a kinase inhibitor and then stimulated using an alternative pathway stimulator; and (3) a PKA or PKC inhibitor and a combination of PKA and PKC stimulators, at ED50 concentrations, were tested. The results for (1) indicate an additive AR response of ED50 concentrations but not for ARmax doses. The results for (2) demonstrate that a kinase inhibitor for one pathway prevents induction of the AR by a stimulator of the alternative pathway. Finally, the results for (3) show that a kinase inhibitor for one pathway prevents induction of the AR by the combined use of separate pathway stimulators. When taken collectively, the present results suggest a convergent mechanism of crosstalk between the PKA and PKC pathways leading to the human sperm AR.
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PMID:Characterization of two second messenger pathways and their interactions in eliciting the human sperm acrosome reaction. 776 51

A protein kinase that causes phosphorylation of serine and threonine residues of casein has been partially purified from goat cauda-epididymal sperm plasma membrane and characterized. The kinase, solubilized from the membrane with 1.0% Triton X-100, was purified to 480-fold by using DEAE-cellulose and casein-Sepharose affinity chromatographic techniques. The kinase is a strongly basic protein with pI of 9.5. The enzyme has a molecular mass of 310 kilodaltons as estimated by Sephacryl S-300 gel exclusion. The kinase showed affinity for protein substrates in the order membrane proteins > casein > phosvitin > histone > protamine. The apparent Km values of the kinase for casein and membrane proteins were 1 and 0.15 mg/mL, respectively. The synthetic peptides Kemptide and poly(Glu80Tyr20) did not serve as substrates of the enzyme. ATP, rather than GTP or PP(i), is the donor of phosphate for the phosphorylation reaction. Cyclic AMP and GMP, NaCl (0.25 M), KCl (0.25 M), Ca2+, calmodulin, phosphatidylserine, and muscle protein kinase inhibitor had no appreciable effect on the kinase activity. Heparin (0.5 microgram/mL) showed high affinity for inhibiting only 40% of the kinase activity, whereas polyamines at a relatively high concentration (5 mM) inhibited 40-50% of the enzymic activity. The kinase appears to be distinct from other protein kinases including casein kinases. The activity of the kinase derived from the purified sperm plasma membrane was markedly (approximately 90%) lost when the intact spermatozoa were pretreated with diazonium salt of sulfanilic acid, a membrane nonpenetrating surface probe.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and characterization of a protein kinase from goat sperm plasma membrane. 784 Sep 41


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