scholarly journals Autophagy Deficiency Promotes β-Lactam Production inPenicillium chrysogenum

2010 ◽  
Vol 77 (4) ◽  
pp. 1413-1422 ◽  
Author(s):  
Magdalena Bartoszewska ◽  
Jan A. K. W. Kiel ◽  
Roel A. L. Bovenberg ◽  
Marten Veenhuis ◽  
Ida J. van der Klei
Keyword(s):  
Penicillium Chrysogenum ◽  
Biosynthetic Pathway ◽  
Morphological Analysis ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Cell Degeneration ◽  
Threonine Kinase ◽  
Enhanced Production ◽  
Electron And Fluorescence Microscopy ◽  
Lactam Antibiotic

ABSTRACTWe have investigated the significance of autophagy in the production of the β-lactam antibiotic penicillin (PEN) by the filamentous fungusPenicillium chrysogenum. In this fungus PEN production is compartmentalized in the cytosol and in peroxisomes. We demonstrate that under PEN-producing conditions significant amounts of cytosolic and peroxisomal proteins are degraded via autophagy. Morphological analysis, based on electron and fluorescence microscopy, revealed that this phenomenon might contribute to progressive deterioration of late subapical cells. We show that deletion of theP. chrysogenumortholog ofSaccharomyces cerevisiaeserine-threonine kinaseatg1results in impairment of autophagy. InP. chrysogenum atg1cells, a distinct delay in cell degeneration is observed relative to wild-type cells. This phenomenon is associated with an increase in the enzyme levels of the PEN biosynthetic pathway and enhanced production levels of this antibacterial compound.

scholarly journals Eukaryotic-type serine/threonine kinase mediated phosphorylation at Thr169 perturbs mycobacterial guanylate kinase activity

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Ghanshyam S. Yadav ◽  
Sandeep K. Ravala ◽  
Sangita Kachhap ◽  
Meghna Thakur ◽  
Abhishek Roy ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Biosynthetic Pathway ◽  
Kinase Activity ◽  
Kinase Assay ◽  
Phosphoryl Group ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Guanylate Kinase ◽  
Mutant Proteins ◽  
Threonine Kinase

Guanylate kinase is an essential and conserved enzyme in nucleotide biosynthetic pathway that transfers phosphoryl group of ATP to GMP for yielding GDP. Here, we report the phosphorylation of guanylate kinase from Mycobacterium tuberculosis (mGmk) by eukaryotic-type Ser/Thr kinase, PknA. Mass spectrometric studies identified Thr101 and Thr169 as phosphorylatable residues in mGmk. To evaluate the significance of phosphorylation in these threonines, two point (T101A and T169A) and one double (T101A-T169A) mutants were generated. The kinase assay with these mutant proteins revealed the major contribution of Thr169 compared with Thr101 in the phosphorylation of mGmk. Kinetic analysis indicated that p-mGmk was deficient in its enzymatic activity compared with that of its un-phosphorylated counterpart. Surprisingly, its phosphoablated (T169A) as well as phosphomimic (T169E) variants exhibited decreased activity as was observed with p-mGmk. Structural analysis suggested that phosphorylation of Thr169 might affect its interaction with Arg166, which is crucial for the functioning of mGmk. In fact, the R166A and R166K mutant proteins displayed a drastic decrease in enzymatic activity compared with that of the wild-type mGmk. Molecular dynamics (MD) studies of mGmk revealed that upon phosphorylation of Thr169, the interactions of Arg165/Arg166 with Glu158, Asp121 and residues of the loop in GMP-binding domain are perturbed. Taken together, our results illuminate the mechanistic insights into phosphorylation-mediated modulation of the catalytic activity of mGmk.

Arabidopsis MLK3, a Plant-specific Casein Kinase 1, Negatively Regulated Flowering and Phosphorylated Histone H3 in vivo

2019 ◽  
Author(s):  
Zhen Wang ◽  
Junmei Kang ◽  
Shangang Jia ◽  
Tiejun Zhang ◽  
Zhihai Wu ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Histone H3 ◽  
Casein Kinase ◽  
Kinase Assay ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Altered Expression ◽  
Casein Kinase 1 ◽  
Threonine Kinase

Abstract Background: Casein kinase 1 (CK1) family members are highly conserved serine/threonine kinase present in most eukaryotes with multiple biological functions. Arabidopsis MUT9-like kinases ( MLKs ) belong to a clade CK1 specific to the plant kingdom and have been implicated collectively in modulating flowering related processes. Three of the four MLKs ( MLK1/2/4 ) have been characterized, however, little is known about MLK3 , the most divergent MLKs. Results: We demonstrated that compared with wild type, mlk3 , a truncated MLK3 , flowered slightly early under long day conditions and ectopic expression of MLK3 rescued the morphological defects of mlk3 , indicating that MLK3 negatively regulates flowering. GA 3 application accelerated flowering of both wild type and mlk3 , suggesting that mlk3 had normal GA response. The recombinant MLK3-GFP was localized in the nucleus exclusively. In vitro kinase assay revealed that the nuclear protein MLK3 phosphorylated histone 3 at threonine 3 (H3T3ph). Mutation of a conserved catalytic residue (Lysine 175) abolished the kinase activity and resulted in failure to complement the early flowering phenotype of mlk3 . Interestingly, the global level of H3T3 phosphorylation in mlk3 did not differ significantly from wild type, suggesting the redundant roles of MLKs in flowering regulation. The transcriptomic analysis demonstrated that 425 genes significantly altered expression level in mlk3 relative to wild type. The mlk3 mlk4 double mutant generated by crossing mlk3 with mlk4 , a loss-of-function mutant of MLK4 showing late flowering, flowered between the two parental lines, suggesting that MLK3 played an antagonistic role to MLK4 in plant transition to flowering. Conclusions: A serine/threonine kinase encoding gene MLK3 is a casein kinase 1 specific to the plant species and represses flowering slightly. MLK3 located in nucleus catalyzes the phosphorylation of histone H3 at threonine 3 in vitro and an intact lysine residue (K175) is indispensible for the kinase activity. This study sheds new light on the delicate control of flowering by the plant-specific CK1 in Arabidopsis.

scholarly journals Relevance of STK11 Mutations Regarding Immune Cell Infiltration, Drug Sensitivity, and Cellular Processes in Lung Adenocarcinoma

2020 ◽  
Vol 10 ◽  
Author(s):  
Zhenqing Li ◽  
Bo Ding ◽  
Jianxun Xu ◽  
Kai Mao ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Drug Sensitivity ◽  
Immune Cell ◽  
Differentially Expressed ◽  
Cell Infiltration ◽  
Immune Cell Infiltration ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Cellular Processes

Serine/threonine kinase 11 (STK11) is one member of the serine/threonine kinase family, which is involved in regulating cell polarity, apoptosis, and DNA damage repair. In lung adenocarcinoma (LUAD), it can play as one tumor suppressor and always be mutated. In this study, we aimed to assess the relevance of STK11 mutations in LUAD, in which we also studied the correlation among immune cell infiltration, drug sensitivity, and cellular processes. By performing the bioinformatics analysis of the Cancer Genome Atlas (TCGA) about LUAD patients, we found that the mutation efficiency of STK11 mutations is about 19%. Additionally, the differentially expressed gene analysis showed that there were 746 differentially expressed genes (DEGs) between LUAD patients with and without STK11 mutations. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis showed that the DEGs were enriched in various tumorigenesis signaling pathways and metabolic processes. Among these DEGs, the top ranking 21 genes were found that they were more frequently mutated in the STK11 mutation group than in the wild-type group (p-value<0.01). Finally, the LUAD patients with STK11 mutations suffered the worse immune cell infiltration levels than the LUAD patients with wild-type. The STK11 gene copy number was correlated with immune cell infiltration. Aiming to develop the therapeutic drugs, we performed Genomics of Drug Sensitivity in Cancer (GDSC) data to identify the potential therapeutic candidate and the results showed that Nutlin-3a(-) may be a sensitive drug for LUAD cases harboring STK11 mutations. The specific genes and pathways shown to be associated with LUAD cases involving STK11 mutations may serve as targets for individualized LUAD treatment.

PRKD2 Serine-Threonine Kinase, a Downstream Effector Of GABP, Plays Essential Roles For The Maintenance Of HSCs

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2430-2430
Author(s):  
Zhong-Fa Yang ◽  
Wang Junling ◽  
Alan G. Rosmarin
Keyword(s):  
Bone Marrow ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Bone Marrow Cells ◽  
Specific Cell ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Hematopoietic Stem ◽  
Threonine Kinase ◽  
Marrow Cells

Abstract Hematopoietic stem cells (HSCs) are the source of all blood lineages, and HSCs must balance quiescence, self-renewal, and differentiation to meet lifelong needs for blood cell development. GABP is an ets-related transcription factor that controls critical genes in myeloid and lymphoid development, and has been implicated in control of HSC growth. GABP is an obligate multimeric transcription factor that includes the DNA-binding ets component, GABPa, along with various GABPb partner proteins. We conditionally deleted Gabpa in mouse bone marrow and found that Gabpa cells have a profound growth disadvantage due to cell cycle arrest in HSCs. We identified Protein Kinase D2 (PRKD2) as a candidate effector of GABP. PRKD2 is a diacyl glycerol- and Protein Kinase C-activated serine-threonine kinase, because deletion of Gabpa markedly reduced PRKD2 expression in normal HSCs and progenitor cells. In a Prkd2ki/ki mouse model, in which two functionally essential phosphorylation serines were inactivated genetically, their bone marrow long term HSCs reduced dramatically and the short term HSCs increased accordingly. Mice transplanted with a 1:1 mixture of Prkd2ki/ki and wild type bone marrow cells demonstrated the decreased proportion of the Prkd2ki/ki bone marrow cells with the corresponding increase of the wild type cells. Although ectopic expression of the human Chronic Myeloid Leukemia (CML) fusion oncogene BCR-ABL in wild type bone marrow cells induced rapid CML development, expression of BCR-ABL in Prkd2ki/ki bone marrow cells failed to develop CML in transplanted recipient mice. Analysis of the peripheral blood, bone marrow and spleen of these mice revealed that the BCR-ABL+, Prkd2ki/ki cells did not express myeloid or lymphoid specific cell surface antigens CD11b, Gr1, B220, or CD3e. They demonstrated an immature blast-like microscopic morphology, and recipient mice transplanted with these cells died before the onset of CML development. We conclude that the phosphorylation activated Prkd2 is required for the maintenance of HSC pool and the development of mature hematopoietic lineages from HSCs. These findings suggest that PRKD2 kinase mediate key downstream events of both PKC and transcription factor GABP, and that PRKD2 may serve as a novel therapeutic target in leukemia. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The mechanism of activation of monomeric B-Raf V600E

2021 ◽  
Author(s):  
Ryan C Maloney ◽  
Mingzhen Zhang ◽  
HYUNBUM JANG ◽  
Ruth Nussinov
Keyword(s):  
Hydrophobic Interactions ◽  
Salt Bridge ◽  
Activation Loop ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Oncogenic Mutations ◽  
In The Wild ◽  
Activation Pathways ◽  
The Impact

Oncogenic mutations in the serine/threonine kinase B-Raf, particularly the V600E mutation, are frequent in cancer, making it a major drug target. Although much is known about B-Raf's active and inactive states, questions remain about the mechanism by which the protein changes between these two states. Here, we utilize molecular dynamics to investigate both wild-type and V600E B-Raf to gain mechanistic insights into the impact of the Val to Glu mutation. The results show that the wild-type and mutant follow similar activation pathways involving an extension of the activation loop and an inward motion of the αC-helix. The V600E mutation, however, destabilizes the inactive state by disrupting hydrophobic interactions present in the wild-type structure while the active state is stabilized through the formation of a salt bridge between Glu600 and Lys507. Additionally, when the activation loop is extended, the αC-helix is able to move between an inward and outward orientation as long as the DFG motif adopts a specific orientation. In that orientation Phe595 rotates away from the αC-helix, allowing the formation of a salt bridge between Lys483 and Glu501. These mechanistic insights have implications for the development of new Raf inhibitors.

scholarly journals Inhibition of Bcr serine kinase by tyrosine phosphorylation.

1996 ◽  
Vol 16 (3) ◽  
pp. 998-1005 ◽  
Author(s):  
J Liu ◽  
Y Wu ◽  
G Z Ma ◽  
D Lu ◽  
L Haataja ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Kinase Activity ◽  
Philadelphia Chromosome ◽  
Wild Type ◽  
Serine Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase

The first exon of the BCR gene encodes a new serine/threonine protein kinase. Abnormal fusion of the BCR and ABL genes, resulting from the formation of the Philadelphia chromosome (Ph), is the hallmark of Ph-positive leukemia. We have previously demonstrated that the Bcr protein is tyrosine phosphorylated within first-exon sequences by the Bcr-Abl oncoprotein. Here we report that in addition to tyrose 177 (Y-177), Y-360 and Y283 are phosphorylated in Bcr-Abl proteins in vitro. Moreover, Bcr tyrosine 360 is phosphorylated in vivo within both Bcr-Abl and Bcr. Bcr mutant Y177F had a greatly reduced ability to transphosphorylate casein and histone H1, whereas Bcr mutants Y177F and Y283F had wild-type activities. In contrast, the Y360F mutation had little effect on Bcr's autophosphorylation activity. Tyrosine-phosphorylated Bcr, phosphorylated in vitro by Bcr-Abl, was greatly inhibited in its serine/threonine kinase activity, impairing both auto- and transkinase activities of Bcr. Similarly, the isolation of Bcr from cells expressing Bcr-Abl under conditions that preserve phosphotyrosine residues also reduced Bcr's kinase activity. These results indicate that tyrosine 360 of Bcr is critical for the transphosphorylation activity of Bcr and that in Ph-positive leukemia, Bcr serine/threonine kinase activity is seriously impaired.

scholarly journals The First Extracellular Domain of Corticotropin Releasing Factor-R1 Contains Major Binding Determinants for Urocortin and Astressin*

Endocrinology ◽  
1998 ◽  
Vol 139 (2) ◽  
pp. 566-570 ◽  
Author(s):  
Marilyn H. Perrin ◽  
Steve Sutton ◽  
Deborah L. Bain ◽  
W. Travis Berggren ◽  
Wylie W. Vale
Keyword(s):  
Extracellular Domain ◽  
Structural Features ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Extracellular Domains ◽  
Membrane Spanning ◽  
Mutant Receptors ◽  
Binding Determinants ◽  
Receptor Family

Abstract The CRF receptors are members of a 7-transmembrane receptor family that includes GH-releasing hormone (GRF), calcitonin, vasoactive intestinal peptide (VIP), secretin, and PTH receptors. To determine the structural features of the CRF receptor that may influence ligand recognition, a series of mutant receptors was analyzed for binding to astressin, a CRF antagonist, and to urocortin, a CRF agonist. Mutant receptors included chimeras between the CRF-R1 and GRF-R or Activin IIB-R, a single membrane spanning receptor serine/threonine kinase. Binding to the mutant receptors was assessed using 125I-[DTyr1] astressin (Ast*) and 125I-[Tyr0]-rat urocortin (Ucn*). There was no binding to a chimeric receptor in which the first extracellular domain (E1c) (i.e. the N-terminal region) of the CRF-R1 was replaced by that of the GRF-R. The complementary chimera in which E1 domain of the GRF-R was replaced by that of the CRF-R1 bound astressin and urocortin with Ki values approximately 10 nm, compared with inhibitory binding dissociation constant (Ki) values of approximately 2–4 nm for the wild-type CRF-R1. The chimera in which E1 of the activin IIB receptor was replaced by E1 of the CRF-R1 bound astressin with a Ki approximately 4 nm. A chimera in which both the first and fourth extracellular domains of the CRF-R1 replaced the corresponding domains of the GRF-R bound astressin with Ki approximately 4 nm and urocortin with a Ki approximately 2 nm. A chimera in which all four extracellular domains of the CRF receptor replaced those of the GRF-R bound astressin and urocortin with Ki values approximately 4 nm and approximately 1 nm, respectively. In conclusion, the major determinants for high affinity binding of CRF agonists and antagonists to CRF-R1 are found in the first extracellular domain of the receptor.

scholarly journals IL-3 induces a Pim1-dependent antiapoptotic pathway in primary human basophils

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 3949-3958 ◽  
Author(s):  
Svetlana A. Didichenko ◽  
Nicole Spiegl ◽  
Thomas Brunner ◽  
Clemens A. Dahinden
Keyword(s):  
Immune Responses ◽  
De Novo ◽  
Pi3 Kinase ◽  
Protein Transduction ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Antiapoptotic Proteins ◽  
Tat Fusion Proteins ◽  
Human Basophils

Abstract The contribution of basophils in allergic disease and other Th2-type immune responses depends on their persistence at sites of inflammation, but the ligands and molecular pathways supporting basophil survival are largely unknown. The comparison of rates of apoptosis and of the expression of antiapoptotic proteins in different human granulocyte types revealed that basophils have a considerably longer spontaneous life span than neutrophils and eosinophils consistent with high levels of constitutive Bcl-2 expression. Interleukin-3 (IL-3) is the only ligand that efficiently protects basophils from apoptosis as evidenced by screening a large number of stimuli. IL-3 up-regulates the expression of the antiapoptotic proteins cIAP2, Mcl-1, and Bcl-XL and induces a rapid and sustained de novo expression of the serine/threonine kinase Pim1 that closely correlates with cytokine-enhanced survival. Inhibitor studies and protein transduction of primary basophils using wild-type and kinase-dead Pim1-Tat fusion-proteins demonstrate the functional importance of Pim1 induction in the IL-3–enhanced survival. Our data further indicate that the antiapoptotic Pim1-mediated pathway operates independently of PI3-kinase but involves the activation of p38 MAPK. The induction of Pim1 leading to PI3-kinase–independent survival as described here for basophils may also be a relevant antiapoptotic mechanism in other terminally differentiated leukocyte types.

scholarly journals Regulation of the Actin Cytoskeleton Organization in Yeast by a Novel Serine/Threonine Kinase Prk1p

1999 ◽  
Vol 144 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Guisheng Zeng ◽  
Mingjie Cai
Keyword(s):  
Actin Cytoskeleton ◽  
Asymmetric Distribution ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Cytoskeleton Organization ◽  
Actin Cytoskeleton Organization ◽  
Related Proteins ◽  
Regulation Of Actin Cytoskeleton

Normal actin cytoskeleton organization in budding yeast requires the function of the Pan1p/ End3p complex. Mutations in PAN1 and END3 cause defects in the organization of actin cytoskeleton and endocytosis. By screening for mutations that can suppress the temperature sensitivity of a pan1 mutant (pan1-4), a novel serine/threonine kinase Prk1p is now identified as a new factor regulating the actin cytoskeleton organization in yeast. The suppression of pan1-4 by prk1 requires the presence of mutant Pan1p. Although viable, the prk1 mutant is unable to maintain an asymmetric distribution of the actin cytoskeleton at 37°C. Consistent with its role in the regulation of actin cytoskeleton, Prk1p localizes to the regions of cell growth and coincides with the polarized actin patches. Overexpression of the PRK1 gene in wild-type cells leads to lethality and actin cytoskeleton abnormalities similar to those exhibited by the pan1 and end3 mutants. In vitro phosphorylation assays demonstrate that Prk1p is able to phosphorylate regions of Pan1p containing the LxxQxTG repeats, including the region responsible for binding to End3p. Based on these findings, we propose that the Prk1 protein kinase regulates the actin cytoskeleton organization by modulating the activities of some actin cytoskeleton-related proteins such as Pan1p/End3p.

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