Identification of a conserved phosphorylation site modulating nuclear lamin polymerization

Stuurman, Nico

doi:10.1016/s0014-5793(96)01464-0

Cited by 28 publications

(35 citation statements)

References 30 publications

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“…Recent work (Muranyi et al 2002;Park and Baines, 2006) demonstrated that herpesvirus infection led to recruitment of PKC to the nuclear membrane and subsequent phosphorylation of lamin B. Lamin B disassembly is associated with specific serine phosphorylation sites (Stuurman, 1997). This modification of the nuclear lamina occurred 10-12 hours post infection and served to promote budding of nucleocapsids at the inner nuclear membrane.…”

Section: ) Discussionmentioning

confidence: 99%

Herpes simplex virus-type 2 infectivity and agents that block gap junctional intercellular communication

et al. 2007

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SUMMARYIn rat liver epithelial (WB) cells, the protein kinase C inhibitor H7 blocked gap junctional intercellular communication (GJIC) and reduced virus infectivity. Octanol, 18-beta-glycyrrhetinic acid, and staurosporine, agents that reduce GJIC, had no effect upon virus infectivity. Previous studies demonstrated that herpes simplex virus-type 2 (HSV-2) infection was accompanied by attenuated GJIC. Of agents tested, only H7 reduced plaque forming unit (pfu) ability in a dose-dependent manner with 100% plaque reduction at 40 μM without evidence of cytotoxicity. Dye transfer indicated that H7 decreased GJIC, although Western blotting revealed that it did not alter phosphorylation of the gap junction protein, connexin 43 (Cx43). Using indirect immunofluorescence, Cx43 was found to localize in membrane plaques in uninfected cells and H-7 did not alter this distribution. However, Cx43 was lost from the membrane at 24 hrs in both H-7 treated and untreated cells infected with HSV-2. Viral infection increased serine phosphorylation, particularly in the nuclear region, and this effect was reduced following H-7 treatment. Thus, H-7 attenuated both GJIC and infectivity of HSV-2 in WB cells but the anti-viral effects were due to reduced nuclear protein phosphorylation rather than alterations in phosphorylation or localization of Cx43. KeywordsGap junctions; Connexin 43; protein kinase C; H7; HSV-2 1) INTRODUCTIONIt has long been known that certain RNA and tumor viruses decrease gap junctional communication among infected cells (Atkinson et al., 1981;Crow et al., 1990;Danave et al., 1994;Ennaji et al., 1995;Faccini et al., 1996, Jou et al., 1995. Recent studies have shown electrophysiologically that down-regulation of gap junctions by herpes simplex virus-type 2 (HSV-2) begins before viral DNA replication, and long before morphological signs of infection (Fischer et al., 2001). In addition, Musee et al. (2002) demonstrated that antiviral agents affect electrical coupling in HSV-2 infected cells in different ways, depending on the mechanism of action of the agent. However, it was not clear if GJIC down-regulation was initiated by the infected cells or by their surrounding uninfected neighbors. If the latter, drugs that reduce GJIC might protect neighboring cells from infection.* To whom all correspondence should be addressed: Phone -(610)-436-2985, Fax -(610)-436-2183, e-mail-mknabb@wcupa.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. How HSV-2 induces gap junctional down-regulation is unknown although both viral-or cellmediated mechanisms are possible. Gap junction channels are...

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Section: ) Discussionmentioning

confidence: 99%

Herpes simplex virus-type 2 infectivity and agents that block gap junctional intercellular communication

et al. 2007

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“…PKC-Several lamin kinases have been identified, including p34 cdc2 , PKC, and PKA (7,9,10,33). In an attempt to determine which kinase(s) mediates interphase sperm lamin B phosphorylation, sperm nuclei were incubated in egg cytosol containing increasing concentrations of the following kinase inhibitors: the nonspecific kinase inhibitors DMAP and staurosporine, the p34 cdc2 -specific inhibitors olomoucine and roscovitine (26), PKI, or the PKC-specific inhibitor chelerythrine (34).…”

Section: Lamin B Phosphorylation Is Inhibited By the Pkc-specific Inhmentioning

confidence: 99%

“…They include cyclin B/p34 cdc2 (7), S6 kinase II (8), protein kinase C (PKC) (4,9), and the cAMP-dependent protein kinase PKA (10). Down-regulation of PKA has also been shown to be essential for mitotic lamina disassembly (11).…”

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Protein Kinase C-mediated Interphase Lamin B Phosphorylation and Solubilization

Collas¹,

Thompson²,

Fields³

et al. 1997

Journal of Biological Chemistry

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Disassembly of the sperm nuclear envelope at fertilization is one of the earliest events in the development of the male pronucleus. We report that nuclear lamina disassembly in interphase sea urchin egg cytosol is a result of lamin B phosphorylation mediated by protein kinase C (PKC). Lamin B of permeabilized sea urchin sperm nuclei incubated in fertilized egg G 1 phase cytosolic extract is phosphorylated within 1 min of incubation and solubilized prior to sperm chromatin decondensation. Phosphorylation is Ca 2؉ -dependent. It is reversibly inhibited by the PKC-specific inhibitor chelerythrine, a PKC pseudosubstrate inhibitor peptide, and a PKC substrate peptide, but not by inhibitors of PKA, p34 cdc2 or calmodulin kinase II. Phosphorylation is inhibited by immunodepletion of cytosolic PKC and restored by addition of purified rat brain PKC. Sperm lamin B is a substrate for rat brain PKC in vitro, resulting in lamin B solubilization. Two-dimensional phosphopeptide maps of lamin B phosphorylated by the cytosolic kinase and by purified rat PKC are virtually identical. These data suggest that PKC is the major kinase required for interphase disassembly of the sperm lamina.The nuclear lamina consists of a polymeric network of intermediate filament molecules, the nuclear lamins, underlying the inner nuclear membrane. The lamina is a dynamic structure, undergoing expansion during interphase of the cell cycle, and depolymerization at mitosis upon breakdown of the nuclear envelope (NE) 1 (1). Mitotic disassembly and reassembly of the lamina is regulated by reversible lamin phosphorylation and dephosphorylation (1). Interphase lamin phosphorylation has also been reported (2-6), but its significance is not fully understood.Several lamin kinases have been identified that promote mitotic lamina solubilization or inhibit lamina assembly in vitro. They include cyclin B/p34 cdc2 (7), S6 kinase II (8), protein kinase C (PKC) (4, 9), and the cAMP-dependent protein kinase PKA (10). Down-regulation of PKA has also been shown to be essential for mitotic lamina disassembly (11). Although not a lamin kinase, Ca 2ϩ /calmodulin-dependent kinase II (CaM kinase II) is also involved in mitotic NE breakdown in sea urchin embryos (12). PKC has also been shown to phosphorylate chicken lamin B 2 in interphase, a process thought to regulate lamin import into the nucleus (13). These observations imply that multiple kinases regulate the dynamics of the nuclear lamina during the cell cycle. The transformation of the sea urchin sperm nucleus into a pronucleus at fertilization provides an opportunity to investigate NE assembly/disassembly during interphase. Sea urchin eggs are fertilized in G 1 phase of the first cell cycle after completion of both meiotic divisions. At fertilization, the sperm NE vesiculates and a new NE reforms around the male pronucleus as the sperm chromatin decondenses (14). Male pronuclear formation has been duplicated in a cell-free system by incubating detergent-permeabilized sperm nuclei in fertilized egg extracts (15)(16)(1...

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“…The nuclear lamina can be reconfigured by phosphorylation while operating as an important anchoring site for specific chromatin regions and contributing to the higher order chromatin organization in interphase (18). The relaxation of the nuclear lamina during the S-phase (19) and its dissolution during mitosis are caused by several different protein kinases, such as suPKC1 kinase in interphase sea urchin eggs (20), cyclin B⅐CDK-1 kinase (21-23), S6 kinase II (24), cAMP-dependent protein kinase (25), and PKC-␣ (26) or PKC-␤ II (27)(28)(29). Dissolution of the nuclear lamina is also needed to package collapsed and fragmented chromatin into apoptotic bodies (30).…”

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Protein Kinase C-βII Is an Apoptotic Lamin Kinase in Polyomavirus-transformed, Etoposide-treated pyF111 Rat Fibroblasts

Chiarini¹,

Whitfield²,

Armato³

et al. 2002

Journal of Biological Chemistry

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The role of protein kinase C-␤ II (PKC-␤ II ) in etoposide (VP-16)-induced apoptosis was studied using polyomavirus-transformed pyF111 rat fibroblasts in which PKC-␤ II specific activity in the nuclear membrane (NM) doubled and the enzyme was cleaved into catalytic fragments. No PKC-␤ II complexes with lamin B1 and/or active caspases were immunoprecipitable from the NM of proliferating untreated cells, but large complexes of PKC-␤ II holoprotein and its catalytic fragments with lamin B1, active caspase-3 and -6, and inactive phospho-CDK-1, but not PKC-␤ I or PKC-␦, could be immunoprecipitated from the NM of VP-16-treated cells, suggesting that PKC-␤ II is an apoptotic lamin kinase. By 30 min after normal nuclei were mixed with cytoplasms from VP-16-treated, but not untreated, cells, PKC-␤ II holoprotein had moved from the apoptotic cytoplasm to the normal NM, and lamin B1 was phosphorylated before cleavage by caspase-6. Lamin B1 phosphorylation was partly reduced, but its cleavage was completely prevented, despite the presence of active caspase-6, by adding a selective PKC-␤s inhibitor, hispidin, to the apoptotic cytoplasms. Thus, a PKC-␤ II response to VP-16 seems necessary for lamin B1 cleavage by caspase-6 and nuclear lamina dissolution in apoptosing pyF111 fibroblasts. The possibility of PKC-␤ II being an apoptotic lamin kinase in these cells was further suggested by lamin B1-bound PKC-␦ being inactive or only slightly active and by PKC-␣ not combining with the lamin.A growing body of evidence suggests that the commitment to and execution of apoptosis are mediated through the phosphorylation of specific proteins by several protein kinases (1). A number of PKC 1 isoforms appear to be among these protein kinases (2, 3). Apoptogens may activate or inactivate and cause the translocation of various PKC isoforms from the cytosol onto cytoskeletal components, cytoplasmic membranes, mitochondria, and/or the nuclear envelope (4 -11); induce their migration from such subcellular structures to nucleoplasmic and/or cytosolic fractions (8, 12); or cause the PKC holoenzymes to be cleaved into N-terminal regulatory and C-terminal catalytic fragments (CFs) by several proteases, including caspases (11,(13)(14)(15). Despite suggestions that a particular PKC isoform (e.g. the novel PKC-␦ and/or its CFs) might play a pivotal role in apoptosis (13,14), the available evidence indicates the involvement and cleavage of novel PKCs (e.g. PKC-⑀ and PKC-), the classical Ca 2ϩ -stimulable PKCs (e.g. PKC-␤), atypical PKCs (e.g. PKC-), and PKC-related (e.g. PRK) kinases in apoptosis (2,3,15). This is the third report from a continuing study of the roles of protein kinase C isozymes in drug-induced apoptosis using a polyomavirus-transformed embryo rat fibroblast, the pyF111 cell, as a model (10, 11). We chose this fibroblast, since it is prone to apoptosis because it cannot make the antiapoptotic Bcl-2 and Bcl-X L proteins but can make the proapoptotic Bax protein (10, 11). We have shown that whereas a surge of the activity of PKC-␦ holopr...

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Identification of a conserved phosphorylation site modulating nuclear lamin polymerization

Cited by 28 publications

References 30 publications

Herpes simplex virus-type 2 infectivity and agents that block gap junctional intercellular communication

Herpes simplex virus-type 2 infectivity and agents that block gap junctional intercellular communication

Protein Kinase C-mediated Interphase Lamin B Phosphorylation and Solubilization

Protein Kinase C-βII Is an Apoptotic Lamin Kinase in Polyomavirus-transformed, Etoposide-treated pyF111 Rat Fibroblasts

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