Identifying tumor suppressors in genetic mosaics: the Drosophila lats gene encodes a putative protein kinase

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1053-1063 ◽  
Author(s):  
T. Xu ◽  
W. Wang ◽  
S. Zhang ◽  
R.A. Stewart ◽  
W. Yu
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Tumor Suppressors ◽  
Sequence Similarity ◽  
Developmental Defects ◽  
Genetic Mosaics ◽  
Putative Protein ◽  
Powerful Approach ◽  
Mutant Cells ◽  
Putative Protein Kinase

We have identified recessive overproliferation mutations by screening and examining clones of mutant cells in genetic mosaics of the fruitfly Drosophila melanogaster. This type of screen provides a powerful approach for identifying and studying potential tumor suppressors. One of the identified genes, lats, has been cloned and encodes a putative protein kinase that shares high levels of sequence similarity with three proteins in budding yeast and Neurospora that are involved in regulation of the cell cycle and growth. Mutations in lats cause dramatic overproliferation phenotypes and various developmental defects in both mosaic animals and homozygous mutants.

scholarly journals Structure–function analysis of yeast piD261/Bud32, an atypical protein kinase essential for normal cell life

2002 ◽  
Vol 364 (2) ◽  
pp. 457-463 ◽  
Author(s):  
Sonia FACCHIN ◽  
Raffaele LOPREIATO ◽  
Silvia STOCCHETTO ◽  
Giorgio ARRIGONI ◽  
Luca CESARO ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Mutational Analysis ◽  
Function Analysis ◽  
Sequence Similarity ◽  
Putative Protein ◽  
Cell Life ◽  
Sds Page ◽  
Structural Homologues ◽  
Putative Protein Kinase

The Saccharomyces cerevisiae YGR262c/BUD32 gene, whose disruption causes a severe pleiotropic phenotype, encodes a 261-residue putative protein kinase, piD261, whose structural homologues have been identified in a variety of organisms, including humans, and whose function is unknown. We have demonstrated previously that piD261, expressed in Escherichia coli as a recombinant protein, is a Ser/Thr kinase, as judged by its ability to autophosphorylate and to phosphorylate casein. Here we describe a mutational analysis showing that, despite low sequence similarity, the invariant residues representing the signature of protein kinases are conserved in piD261 and in its structural homologues, but are embedded in an altered context, suggestive of unique mechanistic properties. Especially noteworthy are: (i) three unique inserts of unknown function within the N-terminal lobe, (ii) the lack of a lysyl residue which in all other Ser/Thr kinases participates in the catalytic event by interacting with the transferred ATP γ-phosphate, and which in piD261 is replaced by a threonine, and (iii) an exceedingly short activation loop including two serines, Ser-187 and Ser-189, whose autophosphorylation accounts for the appearance of an upshifted band upon SDS/PAGE. A mutant in which these serines are replaced by alanines was devoid of the upshifted band and displayed reduced catalytic activity. This would include piD261 in the category of protein kinases activated by phosphorylation, although it lacks the RD (Arg-Asp) motif which is typical of these enzymes.

Cell-cycle-dependent expression of the STK-1 gene encoding a novel murine putative protein kinase

Gene ◽  
1996 ◽  
Vol 169 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Hitoshi Niwa ◽  
Kuniya Abe ◽  
Takahiro Kunisada ◽  
Ken-ichi Yamamura
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Gene Encoding ◽  
Putative Protein ◽  
Cycle Dependent ◽  
Putative Protein Kinase

The cell-cycle-regulated budding yeast gene DBF2, encoding a putative protein kinase, has a homologue that is not under cell-cycle control

Gene ◽  
1991 ◽  
Vol 104 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Jeremy H. Toyn ◽  
Araki Hiroyuki ◽  
Sugino Akio ◽  
Leland H. Johnston
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Budding Yeast ◽  
Cell Cycle Control ◽  
Yeast Gene ◽  
Putative Protein ◽  
Putative Protein Kinase

Suppression of Temperature-Sensitive RAS in S.cerevisiae by a Putative Protein Kinase

ras Oncogenes ◽  
1989 ◽  
pp. 93-97 ◽  
Author(s):  
Elena Carra ◽  
Pietro Masturzo ◽  
Alessandra Vitelli ◽  
Emanuele Burderi ◽  
Irene Lambrinoudaki ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Temperature Sensitive ◽  
Putative Protein ◽  
Putative Protein Kinase

scholarly journals The Acidic Region and Conserved Putative Protein Kinase C Phosphorylation Site in Nef Are Important for SIV Replication in Rhesus Macaques

Virology ◽  
1999 ◽  
Vol 257 (1) ◽  
pp. 138-155 ◽  
Author(s):  
Silke Carl ◽  
A.John Iafrate ◽  
Sabine M. Lang ◽  
Christiane Stahl-Hennig ◽  
Eva M. Kuhn ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Rhesus Macaques ◽  
Phosphorylation Site ◽  
Putative Protein ◽  
Kinase C ◽  
Acidic Region ◽  
Putative Protein Kinase

Starvation promotes Dictyostelium development by relieving PufA inhibition of PKA translation through the YakA kinase pathway

Development ◽  
1999 ◽  
Vol 126 (14) ◽  
pp. 3263-3274 ◽  
Author(s):  
G.M. Souza ◽  
A.M. da Silva ◽  
A. Kuspa
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Mrna Levels ◽  
Wild Type ◽  
Mobility Shift ◽  
Developmental Defects ◽  
C Protein ◽  
Protein Levels ◽  
Cell Extracts ◽  
Puf Protein

When nutrients are depleted, Dictyostelium cells undergo cell cycle arrest and initiate a developmental program that ensures survival. The YakA protein kinase governs this transition by regulating the cell cycle, repressing growth-phase genes and inducing developmental genes. YakA mutants have a shortened cell cycle and do not initiate development. A suppressor of yakA that reverses most of the developmental defects of yakA- cells, but none of their growth defects was identified. The inactivated gene, pufA, encodes a member of the Puf protein family of translational regulators. Upon starvation, pufA- cells develop precociously and overexpress developmentally important proteins, including the catalytic subunit of cAMP-dependent protein kinase, PKA-C. Gel mobility-shift assays using a 200-base segment of PKA-C's mRNA as a probe reveals a complex with wild-type cell extracts, but not with pufA- cell extracts, suggesting the presence of a potential PufA recognition element in the PKA-C mRNA. PKA-C protein levels are low at the times of development when this complex is detectable, whereas when the complex is undetectable PKA-C levels are high. There is also an inverse relationship between PufA and PKA-C protein levels at all times of development in every mutant tested. Furthermore, expression of the putative PufA recognition elements in wild-type cells causes precocious aggregation and PKA-C overexpression, phenocopying a pufA mutation. Finally, YakA function is required for the decline of PufA protein and mRNA levels in the first 4 hours of development. We propose that PufA is a translational regulator that directly controls PKA-C synthesis and that YakA regulates the initiation of development by inhibiting the expression of PufA. Our work also suggests that Puf protein translational regulation evolved prior to the radiation of metazoan species.

Differential effects of putative protein kinase C inhibitors on contraction of rat aortic smooth muscle

1993 ◽  
Vol 264 (4) ◽  
pp. H1300-H1306 ◽  
Author(s):  
Y. Shimamoto ◽  
H. Shimamoto ◽  
C. Y. Kwan ◽  
E. E. Daniel
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Induced Response ◽  
Dependent Manner ◽  
Contractile Responses ◽  
Putative Protein ◽  
Calphostin C ◽  
Kinase C ◽  
Putative Protein Kinase

We investigated effects of three kinds of putative protein kinase C (PKC) inhibitors, calphostin C, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), and stauro-sporine, on aortic muscle contractions induced by KCl, phenylephrine, 12-O-tetradecanoylphorbol-13-acetate (TPA), and phorbol 12, 13-dibutyrate (PDBu). Calphostin C noncompetitively inhibited TPA-induced contractions in a concentration-dependent manner. At 10(-6) M, calphostin C completely abolished responses to TPA and also effectively inhibited PDBu-induced contractions. Such a concentration of calphostin C had no effect on KCl-induced contractions but decreased the maximal tension of phenylephrine-induced response curve by 35.3 +/- 6.6% H-7 (10(-5) M had little effect on TPA-induced contraction but significantly inhibited contractile responses to phenylephrine and KCl. Staurosporine (10(-8) M, 3 x 10(-8) M) inhibited contractile responses to KCl, phenylephrine, and TPA. We suggest that staurosporine and H-7, which are known to act on the catalytic domain of PKC carrying high degree of sequence homology with other protein kinases, are relatively nonselective for PKC. On the other hand, calphostin C acting on the regulatory domain of PKC, which is distinct from other protein kinases, may serve as a relatively more selective PKC inhibitor.

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