scholarly journals A MAP kinase necessary for receptor-mediated activation of adenylyl cyclase in Dictyostelium.

1995 ◽  
Vol 128 (3) ◽  
pp. 405-413 ◽  
Author(s):  
J E Segall ◽  
A Kuspa ◽  
G Shaulsky ◽  
M Ecke ◽  
M Maeda ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Protein Kinase ◽  
Map Kinase ◽  
Adenylyl Cyclase ◽  
Dictyostelium Discoideum ◽  
Developmental Mutant ◽  
Mutant Cells

Analysis of a developmental mutant in Dictyostelium discoideum which is unable to initiate morphogenesis has shown that a protein kinase of the MAP kinase/ERK family affects relay of the cAMP chemotactic signal and cell differentiation. Strains in which the locus encoding ERK2 is disrupted respond to a pulse of cAMP by synthesizing cGMP normally but show little synthesis of cAMP. Since mutant cells lacking ERK2 contain normal levels of both the cytosolic regulator of adenylyl cyclase (CRAC) and manganese-activatable adenylyl cyclase, it appears that this kinase is important for receptor-mediated activation of adenylyl cyclase.

Cell differentiation in a temperature-sensitive stalkless mutant of Dictyostelium discoideum

Development ◽  
1983 ◽  
Vol 74 (1) ◽  
pp. 235-243
Author(s):  
Aiko Amagai ◽  
Shuji Ishida ◽  
Ikuo Takeuchi
Keyword(s):  
Cell Differentiation ◽  
Dictyostelium Discoideum ◽  
Anterior Part ◽  
Cell Mass ◽  
Temperature Sensitive ◽  
Type Conversion ◽  
Spore Mass ◽  
Cell Type Conversion ◽  
Almost All ◽  
Mutant Cells

A temperature-sensitive aggregateless and stalkless mutant was isolated from Dictyostelium discoideum NC-4. The mutant cells cannot aggregate at 27°C, but aggregate and form normal fruiting bodies at 21°C. When the temperature was shifted to 27°C after aggregation at 21°C, almost all of the cells in the aggregate differentiated into spores. Neither stalk cells nor stalk tubes formed at 27°C. Inhibition of stalk formation was not lifted by addition of cyclic AMP. Nevertheless, the proportion of prespore to total cells within the mutant slugs was normal, at both 21 °C and 27 °C. At 27 °C, a slug was transformed into a spherical cell mass at the end of migration, within which pre-existing prespore cells differentiated into spores. The remaining prestalk cells were then converted to prespore cells which later became spores. As the cell-type conversion continued, formation of a spore mass resulted. The development of the mutant is thus consistent with the idea that the presumptive cell differentiation is directly related to the terminal cell differentiation. During migration at 27 °C, the number of prestalk cells decreased in the anterior part of the slug but instead increased at the foot or the rear part, whereas the prestalk—prespore pattern remained normal at 21 °C. The fact that a normal proportion of prespore cells was maintained in spite of their deranged distribution at 27 °C indicates that the regulation of proportion is independent of the formation of pattern.

scholarly journals GTPase-deficient G alpha 16 and G alpha q induce PC12 cell differentiation and persistent activation of cJun NH2-terminal kinases.

1996 ◽  
Vol 16 (2) ◽  
pp. 648-656 ◽  
Author(s):  
L E Heasley ◽  
B Storey ◽  
G R Fanger ◽  
L Butterfield ◽  
J Zamarripa ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Protein Kinase ◽  
Map Kinase ◽  
Neurite Outgrowth ◽  
Neuronal Differentiation ◽  
Pc12 Cells ◽  
Pc12 Cell ◽  
Jnk Activation ◽  
G Alpha Q ◽  
Constitutively Active

Persistent stimulation of specific protein kinase pathways has been proposed as a key feature of receptor tyrosine kinases and intracellular oncoproteins that signal neuronal differentiation of rat pheochromocytoma (PC12) cells. Among the protein serine/threonine kinases identified to date, the p42/44 mitogen-activated protein (MAP) kinases have been highlighted for their potential role in signalling PC12 cell differentiation. We report here that retrovirus-mediated expression of GTPase-deficient, constitutively active forms of the heterotrimeric Gq family members, G alpha qQ209L and G alpha 16Q212L, in PC12 cells induces neuronal differentiation as indicated by neurite outgrowth and the increased expression of voltage-dependent sodium channels. Differentiation was not observed after cellular expression of GTPase-deficient forms of alpha i2 or alpha 0, indicating selectivity for the Gq family of G proteins. As predicted, overexpression of alpha qQ209L and alpha 16Q212L constitutively elevated basal phospholipase C activity approximately 10-fold in PC12 cells. Significantly, little or no p42/44 MAP kinase activity was detected in PC12 cells differentiated with alpha 16Q212L or alpha qQ209L, although these proteins were strongly activated following expression of constitutively active cRaf-1. Rather, a persistent threefold activation of the cJun NH2-terminal kinases (JNKs) was observed in PC12 cells expressing alpha qQ209L and alpha 16Q212L. This level of JNK activation was similar to that achieved with nerve growth factor, a strong inducer of PC12 cell differentiation. Supportive of a role for JNK activation in PC12 cell differentiation, retrovirus-mediated overexpression of cJun, a JNK target, in PC12 cells induced neurite outgrowth. The results define a p42/44 MAP kinase-independent mechanism for differentiation of PC12 cells and suggest that persistent activation of the JNK members of the proline-directed protein kinase family by GTPase-deficient G alpha q and G alpha 16 subunits is sufficient to induce differentiation of PC12 cells.

scholarly journals Constitutively Active Protein Kinase A Disrupts Motility and Chemotaxis in Dictyostelium discoideum

2003 ◽  
Vol 2 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Hui Zhang ◽  
Paul J. Heid ◽  
Deborah Wessels ◽  
Karla J. Daniels ◽  
Tien Pham ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Dictyostelium Discoideum ◽  
Regulatory Subunit ◽  
Computer Assisted ◽  
Normal Velocity ◽  
Wild Type ◽  
Mutant Cells ◽  
Kinase A ◽  
Constitutively Active

ABSTRACT The deletion of the gene for the regulatory subunit of protein kinase A (PKA) results in constitutively active PKA in the pkaR mutant. To investigate the role of PKA in the basic motile behavior and chemotaxis of Dictyostelium discoideum, pkaR mutant cells were subjected to computer-assisted two- and three-dimensional motion analysis. pkaR mutant cells crawled at only half the speed of wild-type cells in buffer, chemotaxed in spatial gradients of cyclic AMP (cAMP) but with reduced efficiency, were incapable of suppressing lateral pseudopods in the front of temporal waves of cAMP, a requirement for natural chemotaxis, did not exhibit the normal velocity surge in response to the front of a wave, and were incapable of chemotaxing toward an aggregation center in natural waves generated by wild-type cells that made up the majority of cells in mixed cultures. Many of the behavioral defects appeared to be the result of the constitutively ovoid shape of the pkaR mutant cells, which forced the dominant pseudopod off the substratum and to the top of the cell body. The behavioral abnormalities that pkaR mutant cells shared with regA mutant cells are discussed by considering the pathway ERK2 —| RegA —| [cAMP] → PKA, which emanates from the front of a wave. The results demonstrate that cells must suppress PKA activity in order to elongate along a substratum, suppress lateral-pseudopod formation, and crawl and chemotax efficiently. The results also implicate PKA activation in dismantling cell polarity at the peak and in the back of a natural cAMP wave.

Adenylyl cyclase and the control of cell differentiation in Dictyostelium discoideum

1977 ◽  
Vol 6 (3-4) ◽  
pp. 229-239 ◽  
Author(s):  
W. Roos ◽  
D. Malchow ◽  
G. Gerisch
Keyword(s):  
Cell Differentiation ◽  
Adenylyl Cyclase ◽  
Dictyostelium Discoideum

scholarly journals A cytosolic cyclic AMP-dependent protein kinase in Dictyostelium discoideum. I. Properties.

1984 ◽  
Vol 259 (1) ◽  
pp. 654-661 ◽  
Author(s):  
I H Majerfeld ◽  
B H Leichtling ◽  
J A Meligeni ◽  
E Spitz ◽  
H V Rickenberg
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Dependent Protein Kinase ◽  
Dependent Protein
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