scholarly journals ACK Family Tyrosine Kinase Activity Is a Component of Dcdc42 Signaling during Dorsal Closure in Drosophila melanogaster

2002 ◽  
Vol 22 (11) ◽  
pp. 3685-3697 ◽  
Author(s):  
Kai Ping Sem ◽  
Baharak Zahedi ◽  
Ivan Tan ◽  
Maria Deak ◽  
Louis Lim ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Leading Edge ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Binding Motif ◽  
Dorsal Closure ◽  
Tyrosine Kinase Activity ◽  
Amino Terminal

ABSTRACT We have characterized Drosophila melanogaster ACK (DACK), one of two members of the ACK family of nonreceptor tyrosine kinases in Drosophila. The ACKs are likely effectors for the small GTPase Cdc42, but signaling by these proteins remains poorly defined. ACK family tyrosine kinase activity functions downstream of Drosophila Cdc42 during dorsal closure of the embryo, as overexpression of DACK can rescue the dorsal closure defects caused by dominant-negative Dcdc42. Similar to known participants in dorsal closure, DACK is enriched in the leading edge cells of the advancing epidermis, but it does not signal through activation of the Jun amino-terminal kinase cascade operating in these cells. Transcription of DACK is responsive to changes in Dcdc42 signaling specifically at the leading edge and in the amnioserosa, two tissues involved in dorsal closure. Unlike other members of the ACK family, DACK does not contain a conserved Cdc42-binding motif, and transcriptional regulation may be one route by which Dcdc42 can affect DACK function. Expression of wild-type and kinase-dead DACK transgenes in embryos, and in the developing wing and eye, reveals that ACK family tyrosine kinase activity is involved in a range of developmental events similar to that of Dcdc42.

DNA sequence, structure, and tyrosine kinase activity of the Drosophila melanogaster Abelson proto-oncogene homolog

1988 ◽  
Vol 8 (2) ◽  
pp. 843-853
Author(s):  
M J Henkemeyer ◽  
R L Bennett ◽  
F B Gertler ◽  
F M Hoffmann
Keyword(s):  
Drosophila Melanogaster ◽  
Tyrosine Kinase ◽  
Dna Sequence ◽  
Kinase Activity ◽  
Essential Gene ◽  
Sequence Similarity ◽  
Homologous Region ◽  
Loss Of Function ◽  
Tyrosine Kinase Activity ◽  
Stage Of Development

We report our molecular characterization of the Drosophila melanogaster Abelson gene (abl), a gene in which recessive loss-of-function mutations result in lethality at the pupal stage of development. This essential gene consists of 10 exons extending over 26 kilobase pairs of genomic DNA. The DNA sequence encodes a protein of 1,520 amino acids with strong sequence similarity to the human c-abl proto-oncogene beginning in the type lb 5' exon and extending through the region essential for tyrosine kinase activity. When the tyrosine kinase homologous region was expressed in Escherichia coli, phosphorylation of proteins on tyrosine residues was observed with an antiphosphotyrosine antibody. These results show that the abl gene is highly conserved through evolution and encodes a functional tyrosine protein kinase required for Drosophila development.

scholarly journals The Drosophila Shark tyrosine kinase is required for embryonic dorsal closure

2000 ◽  
Vol 14 (5) ◽  
pp. 604-614
Author(s):  
Rafael Fernandez ◽  
Fumitaka Takahashi ◽  
Zhao Liu ◽  
Ruth Steward ◽  
David Stein ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Leading Edge ◽  
Dorsal Closure ◽  
Kinase Gene ◽  
Dorsal Midline ◽  
Jnk Signaling ◽  
Amino Terminal ◽  
Tyrosine Kinase Gene ◽  
Epithelial Sheet ◽  
Jnk Signaling Pathway

Dorsal closure (DC) in the Drosophila embryo requires the coordinated interaction of two different functional domains of the epidermal cell layer—the leading edge (LE) and the lateral epidermis. In response to activation of a conserved c-Jun amino-terminal kinase (JNK) signaling module, the dorsal-most layer of cells, which constitute the LE of the stretching epithelial sheet, secrete Dpp, a member of the TGFβ superfamily. Dpp and other LE cell-derived signaling molecules stimulate the bilateral dorsal elongation of cells of the dorsolateral epidermis over the underlaying amnioserosa and the eventual fusion of their LEs along the dorsal midline. We have found that flies bearing a Shark tyrosine kinase gene mutation,shark1, exhibit a DC-defective phenotype. Dpp fails to be expressed in shark1 mutant LE cells. Consistent with these observations, epidermal-specific reconstitution ofshark function or overexpression of an activated form of c-Jun in the shark1 mutant background, rescues the DC defect. Thus, Shark regulates the JNK signaling pathway leading to Dpp expression in LE cells. Furthermore, constitutive activation of the Dpp pathway throughout the epidermis fails to rescue theshark1 DC defect, suggesting that Shark may function in additional pathways in the LE and/or lateral epithelium.

scholarly journals Morphological Differentiation of Oligodendrocytes Requires Activation of Fyn Tyrosine Kinase

1999 ◽  
Vol 145 (6) ◽  
pp. 1209-1218 ◽  
Author(s):  
Donna J. Osterhout ◽  
Amy Wolven ◽  
Rebecca M. Wolf ◽  
Marilyn D. Resh ◽  
Moses V. Chao
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Kinase Inhibitors ◽  
Morphological Differentiation ◽  
Dominant Negative ◽  
Tyrosine Kinase Activity ◽  
Oligodendrocyte Progenitors ◽  
Differentiated Cells ◽  
Process Formation ◽  
Fyn Tyrosine Kinase

In the central nervous system, myelination of axons occurs when oligodendrocyte progenitors undergo terminal differentiation and initiate process formation and axonal ensheathment. Although it is hypothesized that neuron-oligodendrocyte contact initiates this process, the molecular signals are not known. Here we find that Fyn tyrosine kinase activity is upregulated very early during oligodendrocyte progenitor cell differentiation. Concomitant with this increase is the appearance of several tyrosine phosphorylated proteins present only in differentiated cells. The increased tyrosine kinase activity is specific to Fyn, as other Src family members are not active in oligodendrocytes. To investigate the function of Fyn activation on differentiation, we used Src family tyrosine kinase inhibitors, PP1 and PP2, in cultures of differentiating oligodendrocyte progenitors. Treatment of progenitors with these compounds prevented activation of Fyn and reduced process extension and myelin membrane formation. This inhibition was reversible and not observed with related inactive analogues. A similar effect was observed when a dominant negative Fyn was introduced in progenitor cells. These findings strongly suggest that activation of Fyn is an essential signaling component for the morphological differentiation of oligodendrocytes.

Drosophila RhoA regulates the cytoskeleton and cell-cell adhesion in the developing epidermis

Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3173-3183 ◽  
Author(s):  
James W. Bloor ◽  
Daniel P. Kiehart
Keyword(s):  
Cell Adhesion ◽  
Leading Edge ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Cell Physiology ◽  
Dorsal Closure ◽  
Adhesive Properties ◽  
Actin Organization ◽  
On Line ◽  
Cell Cell

The small GTPase Rho is a molecular switch that is best known for its role in regulating the actomyosin cytoskeleton. We have investigated its role in the developing Drosophila embryonic epidermis during the process of dorsal closure. By expressing the dominant negative DRhoAN19 construct in stripes of epidermal cells, we confirm that Rho function is required for dorsal closure and demonstrate that it is necessary to maintain the integrity of the ventral epidermis. We show that defects in actin organization, nonmuscle myosin II localization, the regulation of gene transcription, DE-cadherin-based cell-cell adhesion and cell polarity underlie the effects of DRhoAN19 expression. Furthermore, we demonstrate that these changes in cell physiology have a differential effect on the epidermis that is dependent upon position in the dorsoventral axis. In the ventral epidermis, cells either lose their adhesiveness and fall out of the epidermis or undergo apoptosis. At the leading edge, cells show altered adhesive properties such that they form ectopic contacts with other DRhoAN19-expressing cells. Movies available on-line

scholarly journals DNA sequence, structure, and tyrosine kinase activity of the Drosophila melanogaster Abelson proto-oncogene homolog.

1988 ◽  
Vol 8 (2) ◽  
pp. 843-853 ◽  
Author(s):  
M J Henkemeyer ◽  
R L Bennett ◽  
F B Gertler ◽  
F M Hoffmann
Keyword(s):  
Drosophila Melanogaster ◽  
Tyrosine Kinase ◽  
Dna Sequence ◽  
Kinase Activity ◽  
Essential Gene ◽  
Sequence Similarity ◽  
Homologous Region ◽  
Loss Of Function ◽  
Tyrosine Kinase Activity ◽  
Stage Of Development

We report our molecular characterization of the Drosophila melanogaster Abelson gene (abl), a gene in which recessive loss-of-function mutations result in lethality at the pupal stage of development. This essential gene consists of 10 exons extending over 26 kilobase pairs of genomic DNA. The DNA sequence encodes a protein of 1,520 amino acids with strong sequence similarity to the human c-abl proto-oncogene beginning in the type lb 5' exon and extending through the region essential for tyrosine kinase activity. When the tyrosine kinase homologous region was expressed in Escherichia coli, phosphorylation of proteins on tyrosine residues was observed with an antiphosphotyrosine antibody. These results show that the abl gene is highly conserved through evolution and encodes a functional tyrosine protein kinase required for Drosophila development.

scholarly journals Deletions within the amino-terminal half of the c-src gene product that alter the functional activity of the protein.

1989 ◽  
Vol 9 (3) ◽  
pp. 1109-1119 ◽  
Author(s):  
S P Nemeth ◽  
L G Fox ◽  
M DeMarco ◽  
J S Brugge
Keyword(s):  
Amino Acids ◽  
Tyrosine Kinase ◽  
Gene Product ◽  
Kinase Activity ◽  
Soft Agar ◽  
Gene Products ◽  
Tyrosine Kinase Activity ◽  
Amino Terminal ◽  
Src Gene

To examine how amino acid sequences outside of the catalytic domain of pp60c-src influence the functional activity of this protein, we have introduced deletion mutations within the amino-terminal half of pp60c-src. These mutations caused distinct changes in the biochemical properties of the c-src gene products and in the properties of cells infected with retroviruses carrying these mutant c-src genes. Cells expressing the c-srcNX protein, which contains a deletion of amino acids 15 to 89, displayed a refractile, spindle-shaped morphology, formed intermediate-sized, tightly packed colonies in soft agar, and contained elevated levels of cellular phosphotyrosine-containing proteins. Thus, deletion of amino acids 15 to 89 can activate the kinase activity and transforming potential of the c-src gene product. Deletion of amino acids 112 to 225, however, did not increase the kinase activity or transforming ability of pp60c-src; indeed, deletion of these sequences in c-srcHP suppressed phenotypic alterations induced by pp60c-src. Cells expressing the c-srcNP or c-srcBS gene products (containing deletions of amino acids 15 to 225 and 55 to 169, respectively) displayed a fusiform, refractile morphology and formed diffuse colonies in soft agar; the mutant proteins displayed an increased in vitro protein-tyrosine kinase activity. However, only a few cellular proteins contained elevated levels of phosphotyrosine in vivo. Thus, deletions downstream of amino acid 89 severely restricted the ability of c-src to phosphorylate cellular substrates in vivo without affecting the intrinsic tyrosine kinase activity of the c-src gene product. These results suggest the existence of at least two modulatory regions within the amino-terminal half of pp60c-src that are important for the regulation of tyrosine kinase activity and for the interaction of pp60c-src with cellular substrates.

Deletions within the amino-terminal half of the c-src gene product that alter the functional activity of the protein

1989 ◽  
Vol 9 (3) ◽  
pp. 1109-1119
Author(s):  
S P Nemeth ◽  
L G Fox ◽  
M DeMarco ◽  
J S Brugge
Keyword(s):  
Amino Acids ◽  
Tyrosine Kinase ◽  
Gene Product ◽  
Kinase Activity ◽  
Soft Agar ◽  
Gene Products ◽  
Tyrosine Kinase Activity ◽  
Amino Terminal ◽  
Src Gene

To examine how amino acid sequences outside of the catalytic domain of pp60c-src influence the functional activity of this protein, we have introduced deletion mutations within the amino-terminal half of pp60c-src. These mutations caused distinct changes in the biochemical properties of the c-src gene products and in the properties of cells infected with retroviruses carrying these mutant c-src genes. Cells expressing the c-srcNX protein, which contains a deletion of amino acids 15 to 89, displayed a refractile, spindle-shaped morphology, formed intermediate-sized, tightly packed colonies in soft agar, and contained elevated levels of cellular phosphotyrosine-containing proteins. Thus, deletion of amino acids 15 to 89 can activate the kinase activity and transforming potential of the c-src gene product. Deletion of amino acids 112 to 225, however, did not increase the kinase activity or transforming ability of pp60c-src; indeed, deletion of these sequences in c-srcHP suppressed phenotypic alterations induced by pp60c-src. Cells expressing the c-srcNP or c-srcBS gene products (containing deletions of amino acids 15 to 225 and 55 to 169, respectively) displayed a fusiform, refractile morphology and formed diffuse colonies in soft agar; the mutant proteins displayed an increased in vitro protein-tyrosine kinase activity. However, only a few cellular proteins contained elevated levels of phosphotyrosine in vivo. Thus, deletions downstream of amino acid 89 severely restricted the ability of c-src to phosphorylate cellular substrates in vivo without affecting the intrinsic tyrosine kinase activity of the c-src gene product. These results suggest the existence of at least two modulatory regions within the amino-terminal half of pp60c-src that are important for the regulation of tyrosine kinase activity and for the interaction of pp60c-src with cellular substrates.

scholarly journals The Tyrosine Kinase Activity of c-Src Regulates Actin Dynamics and Organization of Podosomes in Osteoclasts

2008 ◽  
Vol 19 (1) ◽  
pp. 394-404 ◽  
Author(s):  
Olivier Destaing ◽  
Archana Sanjay ◽  
Cecile Itzstein ◽  
William C. Horne ◽  
Derek Toomre ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Tyrosine Kinase ◽  
Life Span ◽  
Actin Polymerization ◽  
Fluorescence Recovery After Photobleaching ◽  
Kinase Activity ◽  
Dominant Negative ◽  
Actin Dynamics ◽  
Tyrosine Kinase Activity ◽  
The Core

Podosomes are dynamic actin-rich structures composed of a dense F-actin core surrounded by a cloud of more diffuse F-actin. Src performs one or more unique functions in osteoclasts (OCLs), and podosome belts and bone resorption are impaired in the absence of Src. Using Src−/−OCLs, we investigated the specific functions of Src in the organization and dynamics of podosomes. We found that podosome number and the podosome-associated actin cloud were decreased in Src−/−OCLs. Videomicroscopy and fluorescence recovery after photobleaching analysis revealed that the life span of Src−/−podosomes was increased fourfold and that the rate of actin flux in the core was decreased by 40%. Thus, Src regulates the formation, structure, life span, and rate of actin polymerization in podosomes and in the actin cloud. Rescue of Src−/−OCLs with Src mutants showed that both the kinase activity and either the SH2 or the SH3 binding domain are required for Src to restore normal podosome organization and dynamics. Moreover, inhibition of Src family kinase activities in Src−/−OCLs by Src inhibitors or by expressing dominant-negative SrcK295Minduced the formation of abnormal podosomes. Thus, Src is an essential regulator of podosome structure, dynamics and organization.

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