Genetic variation of the East Balkan Swine (Sus scrofa) in Bulgaria, revealed by mitochondrial DNA and Y chromosomal DNA.

East Balkan Swine (EBS) Sus scrofa is the only aboriginal domesticated pig breed in Bulgaria and is distributed on the western coast of the Black Sea in Bulgaria. To reveal the breed's genetic characteristics, we analysed mitochondrial DNA (mtDNA) and Y chromosomal DNA sequences of EBS in Bulgaria. Nucleotide diversity (πn ) of the mtDNA control region, including two newly found haplotypes, in 54 EBS was higher (0.014 ± 0.007) compared with that of European (0.005 ± 0.003) and Asian (0.006 ± 0.003) domestic pigs and wild boar. The median-joining network based on the mtDNA control region showed that the EBS and wild boar in Bulgaria comprised mainly two major mtDNA clades, European clade E1 (61.3%) and Asian clade A (38.7%). The coexistence of two mtDNA clades in EBS in Bulgaria may be the relict of historical pig translocation. Among the Bulgarian EBS colonies, the geographical differences in distribution of two mtDNA clades (E1 and A) could be attributed to the source pig populations and/or historical crossbreeding with imported pigs. In addition, analysis of the Y chromosomal DNA sequences for the EBS revealed that all of the EBS had haplotype HY1, which is dominant in European domestic pigs.

Nuclear structure relevant to neutrinoless double beta decay: 76Ge and 76Se.

The possibility of observing neutrinoless double beta decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and measurements of the occupations of valence orbits by nucleons active in the decay can be important. The occupation of valence neutron orbits in the ground states of 76Ge (a candidate for such decay) and 76Se (the daughter nucleus) were determined by precisely measuring cross sections for both neutron-adding and removing transfer reactions. Our results indicate that the Fermi surface is much more diffuse than in theoretical calculations. We find that the populations of at least three orbits change significantly between these two ground states while in the calculations, the changes are confined primarily to one orbit.

Characterization of chemokine receptor expression and cytokine production in circulating CD4+ T cells from patients with atopic dermatitis: up-regulation of C-C chemokine receptor 4 in atopic dermatitis.

BACKGROUND: Th2 and Th1 cells have been suggested to express CCR3/CCR4 and CCR5/CXCR3, respectively. OBJECTIVE: We examined CCR3, CCR4, CCR5 and CXCR3 expression and cytokine production in peripheral blood CD4+ T cells from patients with atopic dermatitis (AD), which has been postulated to be a Th2-type cell-mediated disease, and then analysed the possible correlation between these values and the levels of several clinical parameters. METHODS: Intracellular cytokine production and chemokine receptor expression in peripheral blood CD4+ T cells from 40 AD patients and 20 sex- and age-matched healthy control subjects were studied by flow cytometry. RESULTS: The frequencies of IL-4- and IL-13-producing CD4+ T cells from patients with AD were significantly higher than those from healthy control subjects (IL-4:3.9 +/- 2.1% vs. 1.6 +/- 0.7%, P = 0.0005, IL-13:4.0 +/- 2.1% vs. 1.8 +/- 0.8%, P = 0.0023), whereas the frequencies of IL-2- and IFN-gamma-producing CD4+ T cells were significantly decreased in AD patients (IL-2:38.1 +/- 10.3% vs. 51.3 +/- 6.3%, P = 0.0003, IFN-gamma: 9.9 +/- 3.5% vs. 26.4 +/- 4.6%, P < 0.0001). The percentage of CCR4+ cells in CD4+ CD45RO+ T cells in AD patients was significantly higher than that in healthy control subjects (24.4 +/- 8.0% vs. 10.9 +/- 2.3%, P < 0.0001) and was correlated positively with the total serum IgE, serum lactic dehydrogenase (LDH) level, eosinophil number, eruption score, and IL-4 and IL-13 secretion in CD4+ T cells, and inversely with IL-2 and IFN-gamma secretion in CD4+ T cells. In contrast, CCR3 was not detected on circulating CD4+ T cells even in AD patients. On the other hand, the percentage of CCR5+ or CXCR3+ cells in CD4+ CD45RO+ T cells in AD patients was significantly decreased (CCR5:23.2 +/- 7.0% vs. 28.4 +/- 5.4%, P = 0.023, CXCR3:29.9 +/- 11.4% vs. 38.5 +/- 6.7%, P = 0.028) and was positively correlated with eruption score (P < 0.05). Multiple regression analyses showed that the percentage of CCR4 expression highly correlated with serum IgE, LDH, eosinophil number and eruption in AD patients. CONCLUSION: CCR4+ cells might be involved in the aetiopathogenesis of AD.

Elevated muscle enzymes in a patient with severe hypocalcemia mimicking polymyositis.

Abstract We report a case of hypocalcemic myopathy confounded by polymyositis due to an elevated level of serum creatine kinase (CK). A 30-year-old man was referred to our hospital for the treatment of provisionally diagnosed polymyositis. His presentation with tetany, hyporeflexia, and general fatigue, in addition to muscle weakness on admission, prompted us to scrutinize a blood sample in search of secondary myopathy. Blood chemistry revealed an elevated level of serum CK, marked hypocalcemia, hyperphosphatemia, and a low serum level of intact parathyroid hormone. The Ellsworth Howard test confirmed the diagnosis of hypoparathyroidism. Supplementation with calcium and 1α-hydroxyvitamin D3 improved his muscle weakness rapidly, and his serum CK level returned to the normal range. Hypoparathyroidism should be included in differential diagnoses of elevated serum CK.

Conserved Wat1/Pop3 WD-repeat protein of fission yeast secures genome stability through microtubule integrity and may be involved in mRNA maturation.

Accurate chromosome segregation is dependent upon the integrity of mitotic spindles, which pull each pair of sister chromatids towards opposite poles. In this study, we have characterised fission yeast pop3-5235, a diploidising mutant that is impaired in genome stability. Pop3 is the same as Wat1, a conserved protein containing 7 WD repeats. Pop3/Wat1 has also been isolated from a two-hybrid screen as a binding partner to Prp2, the large subunit of the essential splicing factor U2AF. In wat1 mutants, the cellular amount of alpha-tubulin is decreased to very low levels, which results in compromised microtubules and spindles, consequently leading to unequal chromosome separation. Further analysis shows that, in spite of the binding between Wat1 and Prp2, Wat1 may not be involved directly in splicing reactions per se. Instead, we find that Wat1 is required for the maintenance of alpha-tubulin mRNA levels; moreover, transcript levels of genes other than the alpha-tubulin gene are also equally decreased in this mutant. Wild-type Wat1, but not the mutant protein, forms a large complex in the cell with several other proteins, suggesting that Wat1 functions as a structural linker in the complex. The results suggest that Wat1 plays a role in mRNA maturation as a coupling protein between splicing and synthesis and/or stabilisation.

Fission yeast homologues of the B' subunit of protein phosphatase 2A: multiple roles in mitotic cell division and functional interaction with calcineurin.

BACKGROUND: Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase distributed in eukaryotes from yeast to human, and plays pivotal roles in diverse cellular functions such as metabolism, cell cycle progression, gene expression and development. PP2A holoenzyme is a heterodimer of a catalytic subunit C and a regulatory subunit A, or a heterotrimer of C, A and a variable regulatory subunit consisting of three families; B, B', and PR72. Specific functions for each variable subunit are not well understood. RESULTS: Two fission yeast genes pbp1+ and pbp2+ homologous to the regulatory subunit B' were isolated. Physical in vivo interaction of the gene products with the catalytic subunit was demonstrated. A double disruption haploid mutant (Deltapbp1Deltapbp2) showed growth defect, cell shape and size abnormality, multiseptation and anucleated cell formation due to abnormality in septum positioning. These phenotypes were suppressed by human B' cDNA, indicating the striking conservation of the B' function from yeast to human. Over-expression of fission yeast B' led to growth defects, a loss of cell shape polarity, septal abnormality and anucleated cell formation. Deltapbp1Deltapbp2 and pbp1 null haploids were hypersensitive to calcineurin inhibitors, cyclosporin A and FK506, with which the mutants underwent arrest at post-anaphase and cell lysis. Double disruption of calcineurin and pbp1+, but not pbp2+, genes led to synthetic lethality. CONCLUSION: The fission yeast B' subunit of PP2A plays critical roles in cell shape control and septum formation, and shares essential functions with calcineurin for viability, possibly through their roles in cytokinesis and cell wall integrity.

Antineutrophil cytoplasmic autoantibody specific for proteinase 3 in a patient with shunt nephritis induced by Gemella morbillorum.

A 17-year-old girl had been placed with ventriculoperitoneal, then ventriculoatrial shunts for congenital hydrocephalus since birth. The patient originally was diagnosed as having a lupus-like disease, but later turned out to have shunt nephritis, presenting with fever, proteinuria, pancytopenia, and hypocomplementemia. Antineutrophil cytoplasmic autoantibody specific for proteinase 3 (PR3-ANCA) was detected in her serum. The patient received oral prednisolone and repeated methylprednisolone pulses, with essentially no beneficial effects. A gram-positive coccus, Gemella morbillorum, was recovered from her blood as well as cerebrospinal fluid, and the culture of the shunt catheter established the diagnosis of shunt nephritis. Removal of the shunt catheter improved symptoms dramatically and decreased PR3-ANCA in serum to an undetectable level. Because steroids had no effects and the control of bacterial infection lowered PR3-ANCA levels, the antibody would have been induced by continuous infection with G morbillorum.

GSK-3 kinase Mck1 and calcineurin coordinately mediate Hsl1 down-regulation by Ca2+ in budding yeast.

The Ca2+-activated pathways of Saccharomyces cerevisiae induce a delay in the onset of mitosis through the activation of Swe1, a negative regulatory kinase that inhibits the Cdc28-Clb complex. Calcineurin and Mpk1 activate Swe1 at the transcriptional and post-translational level, respectively, and both pathways are essential for the cell cycle delay. Our genetic screening identified the MCK1 gene, which encodes a glycogen synthetase kinase-3 family protein kinase, as a component of the Ca2+ signaling pathway. Genetic analyses indicated that Mck1 functions downstream of the Mpk1 pathway and down-regulates Hsl1, an inhibitory kinase of Swe1. In medium with a high concentration of Ca2+, Hsl1 was delocalized from the bud neck and destabilized in a manner dependent on both calcineurin and Mck1. Calcineurin was required for the dephosphorylation of autophosphorylated Hsl1. The E3 ubiquitin ligase complex SCF(Cdc4), but not the anaphase-promoting complex (APC), was essential for Hsl1 destabilization. The Ca2+-activated pathway may play a role in the rapid inactivation of Hsl1 at the cell cycle stage(s) when APC activity is low.

Regulation of Wee1 kinase in response to protein synthesis inhibition.

To investigate the mechanism coupling growth (protein synthesis) with cell division, we examined the relationship between the tyrosine kinase Wee1 that inhibits Cdc2-Cdc13 mitosis-inducing kinase by phosphorylating it, and protein synthesis inhibition in fission yeast. The wee1-50 mutant showed supersensitivity to protein synthesis inhibitor, cycloheximide. Wee1 was essential for the G(2) delay upon a partial inhibition of protein synthesis. Indeed, the protein synthesis inhibition caused an increase in the Wee1 protein by the Sty1/Spc1 MAPK-dependent transcriptional and the Sty1/Spc1 MAPK-independent post-transcriptional regulations. Further, the results indicated that the post-transcriptional regulation is important for the G(2) delay.

Subarachnoid hemorrhage and systemic lupus erythematosus.

The frequency, clinical profile, treatment and outcome of subarachnoid hemorrhage (SAH) in patients with systemic lupus erythematosus (SLE) were assessed retrospectively, based on the case records of SLE of the Jichi Medical School Hospital over a 20 year period. Clinically defined SAH was found in 10 (3.9%) out of 258 SLE patients, which represented a frequency higher than previously assumed. Five patients had active SLE and lacked an apparent cause of SAH, other than SLE. A high mortality rate (5/5), no visible aneurysm on angiogram (3/4), and an onset during intractable SLE or after discontinued or no steroid therapy because of medical noncompliance (4/5) were characteristic of patients with active SLE, and thus an earlier successful suppression of SLE, if possible, might have prevented their SAH. In contrast, in the 5 patients with inactive SLE, 2 out of 3 saccular aneurysms were successfully clipped and small bleeding of one patient without aneurysms remitted spontaneously without the need for additional steroid therapy. When one death, which occurred outside of medical care, was excluded, the survival ratio of the hospitalized SAH patients with inactive SLE was significantly better than that with active SLE (3/4 versus 0/5, P=0.0476). In conclusion, the relatively common occurrence of SAH in SLE patients, and a significantly different clinical impact of SAH in respect to active and inactive SLE, were suggested from the results.

A positive screening for drugs that specifically inhibit the Ca2+-signaling activity on the basis of the growth promoting effect on a yeast mutant with a peculiar phenotype.

An inappropriate activation of a signaling pathway in yeast often has a deleterious physiological effect and causes various defects, including growth defects. In a certain genetic background (deltazds1) of Saccharomyces cerevisiae, the cell-cycle progression in G2 is specifically blocked in the medium with CaCl2 by the hyperactivation of the Ca2+-signaling pathways. Here, we developed a novel drug screening procedure designed to detect the active compounds that specifically attenuate the Ca2+-signaling activity on the basis of the ability to abrogate the growth defect of the cells suffering from the hyperactivated Ca2+ signal. Using known calcineurin inhibitors as model compounds, we have established the screening conditions for the drugs that suppress the Ca2+-induced growth inhibition. An indicator strain with an increased drug sensitivity was constructed with a syr1/erg3 null mutation.

Autoantibodies against chaperonin CCT in human sera with rheumatic autoimmune diseases: comparison with antibodies against other Hsp60 family proteins.

Chaperonin CCT containing t-complex polypeptide 1 is a cytosolic molecular chaperone that assists in the folding of actin, tubulin, and other proteins and is a member of the 60-kDa heat shock protein (Hsp60) family. We examined antibody titers against human CCT and other Hsp60 family members in the sera of patients with rheumatic autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematodes, Sjögren syndrome, and mixed connective tissue disease. Autoantibody titers against not only human mitochondrial Hsp60 but also CCT were significantly higher in the sera of patients with rheumatic autoimmune diseases than in healthy control sera. Although immunoglobulin G (IgG) titers against Escherichia coli GroEL were high in all the groups of sera tested, no significant differences in anti-GroEL responses were detected between patients and healthy controls. IgG titers against mycobacterial Hsp65 showed a similar pattern to titers of autoantibodies recognizing GroEL. Immunoabsorption experiments demonstrated that most of the autoantibodies recognizing CCT were cross-reactive with mitochondrial Hsp60, E coli GroEL, and mycobacterial Hsp65. Although most of the anti-Hsp60 IgG recognized CCT, anti-GroEL (or antimycobacterial Hsp65) IgG contained antibodies specific for GroEL (or mycobacterial Hsp65) in addition to antibodies cross-reactive with CCT and Hsp60. Results from immunoblot analyses, together with weak (15% to 20%) amino acid sequence identities between CCT and the other Hsp60 family members, suggested that CCT-reactive autoantibodies recognize conformational epitopes that are conserved among CCT and other Hsp60 family members.

Nucleolin as the earliest target molecule of autoantibodies produced in MRL/lpr lupus-prone mice.

To elucidate the autoantigen against which autoantibodies are produced in the earliest phase of the disease process of systemic lupus erythematosus (SLE), serum samples were collected individually and serially from 10 NZB/NZW F1 and 10 MRL/lpr mice. Using immunoblots with mouse thymoma cell (EL-4) lysates as substrates, all mice were found to generate autoantibody against an either 150-kDa, 110-kDa, 75-kDa, or 55-kDa molecule in as early as 4 weeks. Anti-DNA antibodies occurred almost at the same time or after those against these four molecules. The number of antigens reactive with autoantibodies in immunoblots increased gradually with age. Antibodies against histone molecules were produced after 8 weeks of age. Among the four antigens, the 110-kDa molecule was identified as nucleolin, which is an abundant nucleolar phosphoprotein. Nucleolin binds DNA, RNA, and nucleic acid-binding proteins such as histone H1. Nucleolin is a target of granzyme A of cytotoxic T cells, and autoantibodies against it are found in sera from patients with SLE as well as from those with various viral infections. These results indicate that nucleolin is one of the immunodominant molecules that break down self-tolerance and initiate autoantibody-spreading in a mouse model of SLE.

[Rapidly progressed secondary amyloidosis in a patient with Still's disease with gamma-allele in his SAA 1 gene].

A fifteen-year-old boy was admitted to our hospital because of lower abdominal pain, watery diarrhea and mucobloody stool. Two years before admission, he was diagnosed to have Still's disease presenting with polyarthritis, sore throat, remittent fever and typical skin rash. He had been treated with non-steroidal anti-inflammatory agents, oral prednisolone and low-dose methotrexate. Although he was almost free of symptoms during the next two years, serum C-reactive protein (CRP) levels continued to be elevated moderately. He began to complain of lower abdominal pain and loose stool in May 1997 and came down with mucous-bloody diarrhea in June. Laboratory data on admission showed an elevated level of serum CRP (13.9 mg/dl). The biopsy of the stomach, ileum, sigmoid colon and rectum revealed the deposition of amyloid protein of AA type, which confirmed the diagnosis of secondary amyloidosis. The dose of prednisolone was increased and dimethyl sulfoxide per os or rectum was instituted, which improved his gastro-intestinal symptoms to some extent. However, fever, arthritis and diarrhea recurred along with tapered prednisolone dosage. In addition to gastro-intestinal symptoms, arrhythmia and proteinuria appeared. These symptoms were considered to reflect general deposition of amyloid in his body. He is now on immunosuppressive agent and high-dose prednisolone. Several studies report the higher frequency of gamma-allele of SAA 1 gene in the cases of rheumatoid arthritis with AA-amyloidosis than in those without. In the patient presented here, molecular biological analysis revealed that his SAA 1 gene was composed of beta- and gamma-allele. The presence of gamma-allele in his SAA 1 gene might be one of the factors that predisposed him for generalized deposition of amyloid protein in such a short period of time.

In vitro and in vivo inhibition of activation induced T cell apoptosis by bucillamine.

OBJECTIVE: To investigate the mechanism of autoimmune phenomena, occasionally seen in patients with rheumatoid arthritis treated with bucillamine (BUC) and D-penicillamine (D-Pen), by evaluating their effects on apoptosis of T cells induced by T cell receptor activation or dexamethasone. METHODS: In vitro apoptosis was induced in a T cell hybridoma (SSP3.7) and a B cell line (WEHI 231) by activation of respective receptors or dexamethasone, in the presence or absence of BUC or D-Pen. In vivo apoptosis was induced in BALB/c mice by staphylococcal enterotoxin B (SEB), with or without BUC or D-Pen, and thymocytes were examined for it by FACS. RESULTS: Stimulation with anti-CD3 and dexamethasone induced apoptosis in 72% and 71% of SSP3.7 cells, respectively. However, only 16% of SSP3.7 cells became apoptotic by anti-CD3 when BUC was added to the culture media. By contrast, 80% of SSP3.7 cells became apoptotic when stimulated by dexamethasone, even in the presence of BUC. BUC did not affect apoptosis of WEHI 231 cells induced by anti-IgM. Although SA981 (a metabolite of BUC) inhibited apoptosis of SSP3.7 cells induced by anti-CD3, D-Pen did not. BUC, SA981, or D-Pen did not significantly influence the level of interleukin 2 secretion stimulated by anti-CD3. In contrast, both BUC and D-Pen inhibited apoptosis of Vbeta8+ thymocytes induced in vivo by SEB superantigen. Neither BUC nor D-Pen significantly changed the number of CD4+CD8+ thymocytes in BALB/c mice injected with dexamethasone. CONCLUSION: BUC decreased, while D-Pen did not, the apoptosis of T cells stimulated by anti-CD3 in vitro, although they both inhibited the deletion of immature thymocytes reactive with SEB in vivo. This may explain autoimmune phenomena sometimes seen during the treatment of rheumatic patients with these drugs.

Overproduction of elongation factor 1alpha, an essential translational component, causes aberrant cell morphology by affecting the control of growth polarity in fission yeast.

BACKGROUND: Elongation factor 1alpha (EF1alpha), an essential component of the eukaryotic translational machinery, has been shown to possess various biochemical and biological activities, including F-actin-binding and -bundling, microtubule- severing, and the activity of making fibroblasts highly susceptible to transformation. However, our understanding of the biological significance of EF1alpha with respect to these various biochemical or biological activities remains limited. Here we report the identification of EF1alpha-encoding genes as genes whose over-expression causes aberrant cell morphology in fission yeast. RESULTS: Overproduction of EF1alpha caused aberrant cell morphology-elliptic, curved or branched-and growth defects in yeast cells at high temperatures. EF1alpha-overproducing cells showed a supersensitivity to the actin inhibitor cytochalasin D and to the tubulin inhibitor thiabendazole. Genetic analyses using cdc mutants suggested that excess EF1alpha disturbed the establishment and the maintenance of growth polarity in the G1 phase by pre- venting the localization of F-actin to the polarized growing site and the organization of microtubules. Results from DNase I column chromatography indicated that EF1alpha was bound to G-actin. Indeed, the fission yeast actin was immunoprecipitated along with EF1alpha. Moreover, the temperature sensitivity caused by the overproduction of EF1alpha was restored by co-overproduction of actin. CONCLUSIONS: Fission yeast EF1alpha has the ability to alter the cell morphology of yeast by affecting the control of actin and microtubule cytoskeletons.

Functional dissection and hierarchy of tubulin-folding cofactor homologues in fission yeast.

We describe the isolation of fission yeast homologues of tubulin-folding cofactors B (Alp11) and E (Alp21), which are essential for cell viability and the maintenance of microtubules. Alp11(B) contains the glycine-rich motif (the CLIP-170 domain) involved in microtubular functions, whereas, unlike mammalian cofactor E, Alp21(E) does not. Both mammalian and yeast cofactor E, however, do contain leucine-rich repeats. Immunoprecipitation analysis shows that Alp11(B) interacts with both alpha-tubulin and Alp21(E), but not with the cofactor D homologue Alp1, whereas Alp21(E) also interacts with Alp1(D). The cellular amount of alpha-tubulin is decreased in both alp1 and alp11 mutants. Overproduction of Alp11(B) results in cell lethality and the disappearance of microtubules, which is rescued by co-overproduction of alpha-tubulin. Both full-length Alp11(B) and the C-terminal third containing the CLIP-170 domain localize in the cytoplasm, and this domain is required for efficient binding to alpha-tubulin. Deletion of alp11 is suppressed by multicopy plasmids containing either alp21(+) or alp1(+), whereas alp21 deletion is rescued by overexpression of alp1(+) but not alp11(+). Finally, the alp1 mutant is not complemented by either alp11(+) or alp21(+). The results suggest that cofactors operate in a linear pathway (Alp11(B)-Alp21(E)-Alp1(D)), each with distinct roles.

Characterization of the 4C8 antigen involved in transendothelial migration of CD26(hi) T cells after tight adhesion to human umbilical vein endothelial cell monolayers.

In extravasation of T cells, little is known about the mechanisms of transendothelial migration subsequent to the T cells' tight adhesion to endothelium. To investigate these mechanisms, we developed a monoclonal antibody (mAb), termed anti-4C8, that blocks transmigration but not adhesion in a culture system in which high CD26-expressing (CD26(hi)) T cells preferentially migrate through human umbilical vein endothelial cell (HUVEC) monolayers cultured on collagen gels. Anti-4C8 reacted with all CD3(+) T cells and monocytes but not neutrophils or HUVECs. The structure defined by this antibody was an 80-kD molecule. The mAb at 1 mug/ml inhibited 80-90% of migration of CD3(+) T cells through unstimulated and interferon gamma-stimulated HUVEC monolayers without interfering with adhesion and cell motility. When added to the cultures after the adhesion, anti-4C8 completely blocked subsequent transmigration of adherent T cells. Phase-contrast and electron microscopy revealed that T cells are arrested at the intercellular junctions of HUVECs in the presence of anti-4C8. Anti-4C8 exhibited agonistic effects on resting T cells without other stimuli under culture conditions in which anti-4C8 can stimulate T cells. First, in the checkerboard assay using collagen gels, the antibody promoted chemokinetic migration of the cells in a dose-dependent manner from 0.1 to 10 mug/ml. The predominant population of T cells that migrated into collagen gels with impregnated anti-4C8 were CD26(hi). Second, solid-phase-immobilized anti-4C8 induced adhesion of T cells to the substrate, often with polarizations in cell shape and large pseudopods rich in filamentous (F-) actin. Third, soluble anti-4C8 augmented F-actin content preferentially in CD26(hi) T cells when added to T cells at a high dose of 10 mug/ml. Finally, both anti-4C8-induced chemokinetic migration and transendothelial migration were inhibited by pretreatment of T cells with pertussis toxin. These findings suggest that stimulation via the 4C8 antigen increases cell motility of CD26(hi) cells with profound cytoskeletal changes through signaling pathways including G proteins. The 4C8 antigen may be involved in preferential transmigration of CD26(hi) cells adherent to HUVECs.

Fission yeast alpha-glucan synthase Mok1 requires the actin cytoskeleton to localize the sites of growth and plays an essential role in cell morphogenesis downstream of protein kinase C function.

In fission yeast protein kinase C homologues (Pck1 and Pck2) are essential for cell morphogenesis. We have isolated mok1(+) in a genetic screen to identify downstream effectors for Pck1/2. mok1(+) is essential for viability and encodes a protein that has several membrane-spanning domains and regions homologous to glucan metabolic enzymes. mok1 mutant shows abnormal cell shape, randomization of F-actin and weak cell wall. Biochemical analysis shows that Mok1 appears to have alpha-glucan synthase activity. Mok1 localization undergoes dramatic alteration during the cell cycle. It localizes to the growing tips in interphase, the medial ring upon mitosis, a double ring before and dense dot during cytokinesis. Double immunofluorescence staining shows that Mok1 exists in close proximity to actin. The subcellular localization of Mok1 is dependent upon the integrity of the F-actin cytoskeleton. Conversely, overexpression of mok1(+) blocks the translocation of cortical actin from one end of the cell to the other. pck2 mutant is synthetically lethal with mok1 mutant, delocalizes Mok1 and shows a lower level of alpha-glucan. These results indicate that Mok1 plays a crucial role in cell morphogenesis interdependently of the actin cytoskeleton and works as one of downstream effectors for Pck1/2.