scholarly journals Phosphorylation of the rat pancreatic bile-salt-dependent lipase by casein kinase II is essential for secretion

1999 ◽  
Vol 345 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Eric PASQUALINI ◽  
Nathalie CAILLOL ◽  
Anne VALETTE ◽  
Roland LLOUBES ◽  
Alain VERINE ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Bile Salt ◽  
Specific Inhibitor ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Pancreatic Cell ◽  
Α Subunit ◽  
Intracellular Membranes

Bile-salt-dependent lipase (BSDL, EC 3.1.1.-) is an enzyme expressed by the pancreatic acinar cells and secreted as a component of the pancreatic juice of all examined species. During its secretion route BSDL is associated with intracellular membranes. This association allows the complete glycosylation of the enzyme or participates in the inhibition of the enzyme activity, which can deleterious for the acinar pancreatic cell. Thereafter, the human BSDL is phosphorylated by a serine/threonine protein kinase and released from intracellular membranes. In the present study, we show that the rat pancreatic BSDL, expressed by AR4-2J cells used as a model, is phosphorylated by a protein kinase that is insensitive to inhibitors of protein kinases A, C or G and that the phosphorylation process is favoured by okadaic acid (an inhibitor of protein phosphatases 1 and 2A). However, 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB), which is a specific inhibitor of casein kinase II, abolishes the phosphorylation in vitro of BSDL within micro- somes of AR4-2J pancreatic cells. We showed further that the α-subunit of casein kinase II co-locates with BSDL within the lumenal compartment of the Golgi. Genistein, which perturbs the trans-Golgi network, also inhibits the phosphorylation of BSDL, suggesting that this post-translational modification of BSDL probably occurred within this cell compartment. The inhibition of the phosphorylation of BSDL by DRB also decreases the rate at which the enzyme is secreted. Under the same conditions, the rate of α-amylase secretion was not modified. These data strongly suggest that phosphorylation is a post-translational event, which appears to be essential for the secretion of BSDL.

Nucleoplasmin associates with and is phosphorylated by casein kinase II

1995 ◽  
Vol 108 (2) ◽  
pp. 779-787 ◽  
Author(s):  
I. Vancurova ◽  
T.M. Paine ◽  
W. Lou ◽  
P.L. Paine
Keyword(s):  
Protein Kinase ◽  
Polyclonal Antibody ◽  
Nuclear Transport ◽  
Specific Inhibitor ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Transferase Activity ◽  
Catalytic Subunits ◽  
Kinetics Of

Nucleoplasmin is a phosphorylated nuclear-accumulating protein. We report herein that the kinetics of its cytoplasm-->nucleus transport are affected by its degree of phosphorylation. Therefore, we sought to identify any protein kinase which specifically associates with nucleoplasmin. We discovered that nucleoplasmin co-isolates by two independent methods (immunoabsorption and chromatography) in a complex including a kinase which phosphorylates nucleoplasmin. The co-purifying kinase is casein kinase II-like because: (i) it phosphorylates casein; (ii) its phospho-transferase activity can be competed out by GTP; (iii) it is stimulated by polylysine; and (iv) it is inhibited by heparin. Moreover, a polyclonal antibody to the alpha (38 kDa) and alpha' (36 kDa) catalytic subunits of casein kinase II specifically recognizes 38 and 36 kDa polypeptides in the nucleoplasmin-complex, and a specific inhibitor of casein kinase II inhibits nucleoplasmin's nuclear transport. Additionally, we found that phosphorylation of nucleoplasmin by its associated casein kinase II is strongly inhibited by histones and that, in addition to nucleoplasmin, another protein (p100) in the nucleoplasmin-complex is phosphorylated by casein kinase II.

scholarly journals Association of bile-salt-dependent lipase with membranes of human pancreatic microsomes is under the control of ATP and phosphorylation

1997 ◽  
Vol 327 (2) ◽  
pp. 527-535 ◽  
Author(s):  
Eric PASQUALINI ◽  
Nathalie CAILLOL ◽  
Eric MAS ◽  
Nadine BRUNEAU ◽  
Doris LEXA ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Bile Salt ◽  
Specific Inhibitor ◽  
Dietary Lipid ◽  
Pancreatic Acinar Cells ◽  
Acetoxymethyl Ester ◽  
Secretion Pathway ◽  
Calphostin C ◽  
First Time

Bile-salt-dependent lipase (BSDL) is secreted by the pancreas into the duodenum, where it catalyses the hydrolysis of dietary lipid esters on activation by bile salts. The secretion pathway of BSDL is comparable with that of other digestive enzymes produced by pancreatic acinar cells. However, in contrast with these other enzymes, BSDL is partly associated with endoplasmic reticulum membranes as part of a folding complex, including a Grp94-related protein to which BSDL is transiently linked. The release of BSDL from membranes occurs once its glycosylation is completed [Bruneau and Lombardo (1995) J. Biol. Chem. 270, 13524-13533]. In the present study, investigations concerning the mechanism of association/dissociation of BSDL with membranes of microsomes were performed. For this purpose the role of ATP and that of the possible phosphorylation of BSDL were examined. For the first time, it is shown that human pancreatic BSDL is phosphorylated, probably at a serine residue, during its transport within the acinar cell. The phosphorylation of BSDL is provoked by calphostin C, an inhibitor of protein kinase C. In the presence of 1-(isoquinolinesulphonyl)2-methylpiperazine, a non-specific inhibitor of serine/threonine protein kinase A, C or G, or of calcium chelator 1,2-bis(O-aminophenoxy)ethane-N,N,Nʹ,Nʹ-tetra-acetic tetra(acetoxymethyl)ester, the phosphorylation of BSDL elicited by calphostin C is abolished. These data suggested that the phosphorylation of BSDL within human pancreatic microsomes is under the control of a cascade of protein kinases. We have also shown that the phosphorylation of BSDL appears to be involved in the release of the enzyme from microsome membranes. Nevertheless ATP, which modifies the conformation of BSDL, triggers this association, and an unhydrolysable ATP analogue was unable to promote it.

Inhibition of protein kinase C- and casein kinase II-mediated phosphorylation of GAP-43 by S100β

1994 ◽  
Vol 25 (3-4) ◽  
pp. 297-304 ◽  
Author(s):  
Li-Hsien Lin ◽  
Linda J. Van Eldik ◽  
Neil Osheroff ◽  
Jeanette J. Norden
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Kinase C

Identification of Glycyrrhizin-Binding Protein Kinase as Casein Kinase II and Characterization of Its Associated Phosphate Acceptors in Mouse Liver

1996 ◽  
Vol 227 (1) ◽  
pp. 102-109 ◽  
Author(s):  
Shigeyoshi Harada ◽  
Atsushi Karino ◽  
Yoshihito Shimoyama ◽  
Fazel Shamsa ◽  
Kenzo Ohtsuki
Keyword(s):  
Protein Kinase ◽  
Mouse Liver ◽  
Binding Protein ◽  
Casein Kinase Ii ◽  
Casein Kinase

MPM-2 antibody-reactive phosphorylations can be created in detergent-extracted cells by kinetochore-bound and soluble kinases

1997 ◽  
Vol 110 (17) ◽  
pp. 2013-2025 ◽  
Author(s):  
L. Renzi ◽  
M.S. Gersch ◽  
M.S. Campbell ◽  
L. Wu ◽  
S.A. Osmani ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Hela Cell ◽  
Map Kinase ◽  
Kinase Inhibitors ◽  
Casein Kinase Ii ◽  
Cell Extract ◽  
Casein Kinase ◽  
Mitotic Chromosomes ◽  
Phosphatase Inhibitors ◽  
Hela Cell Extract

The MPM-2 antibody labels mitosis-specific and cell cycle-regulated phosphoproteins. The major phosphoproteins of mitotic chromosomes recognized by the MPM-2 antibody are DNA topoisomerase II (topoII) alpha and beta. In immunofluorescence studies of PtK1 cytoskeletons, prepared by detergent lysis in the presence of potent phosphatase inhibitors, the MPM-2 antibody labels phosphoproteins found at kinetochores, chromosome arms, midbody and spindle poles of mitotic cells. In cells extracted without phosphatase inhibitors, labeling of the MPM-2 antibodies at kinetochores is greatly diminished. However, in cytoskeletons this epitope can be regenerated through the action of kinases stably bound at the kinetochore. Various kinase inhibitors were tested in order to characterize the endogenous kinase responsible for these phosphorylations. We found that the MPM-2 epitope will not rephosphorylate in the presence of the broad specificity kinase inhibitors K-252a, staurosporine and 2-aminopurine. Several other inhibitors had no effect on the rephosphorylation indicating that the endogenous MPM-2 kinase at kinetochores is not p34cdc2, casein kinase II, MAP kinase, protein kinase A or protein kinase C. The addition of N-ethylmaleimide inactivated the endogenous kinetochore kinase; this allowed testing of several purified kinases in the kinetochore rephosphorylation assay. Active p34cdc2-cyclin B, casein kinase II and MAP kinase could not generate the MPM-2 phosphoepitope. However, bacterially expressed NIMA from Aspergillus and ultracentrifuged mitotic HeLa cell extract were able to catalyze the rephosphorylation of the MPM-2 epitope at kinetochores. Furthermore, fractionation of mitotic HeLa cell extract showed that kinases that create the MPM-2 epitope at kinetochores and chromosome arms are distinct. Our results suggest that multiple kinases (either soluble or kinetochore-bound), including a homolog of mammalian NIMA, can create the MPM-2 phosphoepitope. The kinetochore-bound kinase that catalyzes the formation of the MPM-2 phosphoepitope may play an important role in key events such as mitotic kinetochore assembly and sister chromatid separation at anaphase.

scholarly journals Casein kinase II is required for efficient transcription by RNA polymerase III.

1996 ◽  
Vol 16 (3) ◽  
pp. 892-898 ◽  
Author(s):  
D J Hockman ◽  
M C Schultz
Keyword(s):  
Protein Kinase ◽  
Rna Polymerase ◽  
Rna Polymerase Iii ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Rna Polymerases ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Polymerase Iii

Casein kinase II (CKII) is a ubiquitous and highly conserved serine/threonine protein kinase found in the nucleus and cytoplasm of most cells. Using a combined biochemical and genetic approach in the yeast Saccharomyces cerevisiae, we assessed the role of CKII in specific transcription by RNA polymerases I, II, and III. CKII is not required for basal transcription by RNA polymerases I and II but is important for polymerase III transcription. Polymerase III transcription is high in extracts with normal CKII activity but low in extracts from a temperature-sensitive mutant that has decreased CKII activity due to a lesion in the enzyme's catalytic alpha' subunit. Polymerase III transcription of 5S rRNA and tRNA templates in the temperature-sensitive extract is rescued by purified, wild-type CKII. An inhibitor of CKII represses polymerase III transcription in wild-type extract, and this repression is partly overcome by supplementing reaction mixtures with active CKII. Finally, we show that polymerase III transcription in vivo is impaired when CKII is inactivated. Our results demonstrate that CKII, an oncogenic protein kinase previously implicated in cell cycle and growth control, is required for high-level transcription by RNA polymerase III.

scholarly journals Identifying and characterizing casein kinase II in human platelets

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3517-3523 ◽  
Author(s):  
CH Hoyt ◽  
CJ Oh ◽  
JB Beekman ◽  
DW Litchfield ◽  
KM Lerea
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Casein Kinase Ii ◽  
Human Platelets ◽  
Casein Kinase ◽  
Immunogold Electron Microscopy ◽  
Beta Subunits ◽  
Specific Substrate ◽  
Substrate Peptide ◽  
Independent Protein

Abstract We have recently shown that inhibition of protein phosphatases in platelets causes increases in protein phosphorylations with a concomitant inhibition of platelet responses. The burst in protein phosphorylation appears to be catalyzed by messenger-independent protein kinases. The aim of the present study was to characterize the presence of broad families of protein kinases found in platelets. Lysates of control and thrombin-stimulated platelets were prepared, and proteins were separated on MONO Q fast protein liquid chromatography. In addition to the presence of histone protein kinase and tyrosine kinase activities, human platelets contain casein kinase II (CKII) activity as assessed by phosphorylation of a specific substrate peptide. Western blot analysis and immunogold electron microscopy studies further showed the presence of alpha-, alpha'-, and beta- subunits of CKII. The enzyme appears to be distributed throughout the cytosol and not secreted after thrombin treatment. Immunoprecipitation studies suggest that at least some of the holoenzymes exist as an alpha alpha' beta 2 complex. Although no activation of the enzyme was detected after thrombin treatment, our results show that CKII is a major messenger-independent protein kinase in platelets.

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