scholarly journals Signal transduction, chemotaxis, and cell aggregation in Dictyostelium discoideum cells without myosin heavy chain

1988 ◽  
Vol 128 (1) ◽  
pp. 158-163 ◽  
Author(s):  
Dorien J.M. Peters ◽  
David A. Knecht ◽  
William F. Loomis ◽  
Arturo De Lozanne ◽  
James Spudich ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Myosin Heavy Chain ◽  
Dictyostelium Discoideum ◽  
Heavy Chain ◽  
Cell Aggregation

scholarly journals A Calcineurin-NFATc3-Dependent Pathway Regulates Skeletal Muscle Differentiation and Slow Myosin Heavy-Chain Expression

2000 ◽  
Vol 20 (17) ◽  
pp. 6600-6611 ◽  
Author(s):  
Ulrike Delling ◽  
Jolana Tureckova ◽  
Hae W. Lim ◽  
Leon J. De Windt ◽  
Peter Rotwein ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Signal Transduction ◽  
Gene Transfer ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Myogenic Differentiation ◽  
Fiber Type ◽  
Slow Myosin ◽  
Slow Myosin Heavy Chain ◽  
Myocyte Differentiation

ABSTRACT The differentiation and maturation of skeletal muscle cells into functional fibers is coordinated largely by inductive signals which act through discrete intracellular signal transduction pathways. Recently, the calcium-activated phosphatase calcineurin (PP2B) and the family of transcription factors known as NFAT have been implicated in the regulation of myocyte hypertrophy and fiber type specificity. Here we present an analysis of the intracellular mechanisms which underlie myocyte differentiation and fiber type specificity due to an insulinlike growth factor 1 (IGF-1)–calcineurin–NFAT signal transduction pathway. We demonstrate that calcineurin enzymatic activity is transiently increased during the initiation of myogenic differentiation in cultured C2C12 cells and that this increase is associated with NFATc3 nuclear translocation. Adenovirus-mediated gene transfer of an activated calcineurin protein (AdCnA) potentiates C2C12 and Sol8 myocyte differentiation, while adenovirus-mediated gene transfer of noncompetitive calcineurin-inhibitory peptides (cain or ΔAKAP79) attenuates differentiation. AdCnA infection was also sufficient to rescue myocyte differentiation in an IGF-depleted myoblast cell line. Using 10T1/2 cells, we demonstrate that MyoD-directed myogenesis is dramatically enhanced by either calcineurin or NFATc3 cotransfection, while a calcineurin inhibitory peptide (cain) blocks differentiation. Enhanced myogenic differentiation directed by calcineurin, but not NFATc3, preferentially specifies slow myosin heavy-chain expression, while enhanced differentiation through mitogen-activated protein kinase kinase 6 (MKK6) promotes fast myosin heavy-chain expression. These data indicate that a signaling pathway involving IGF-calcineurin-NFATc3 enhances myogenic differentiation whereas calcineurin acts through other factors to promote the slow fiber type program.

scholarly journals Myosin heavy chain kinases play essential roles in Ca2+, but not cAMP, chemotaxis and the natural aggregation of Dictyostelium discoideum

2012 ◽  
Vol 125 (20) ◽  
pp. 4934-4944 ◽  
Author(s):  
D. Wessels ◽  
D. F. Lusche ◽  
P. A. Steimle ◽  
A. Scherer ◽  
S. Kuhl ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Dictyostelium Discoideum ◽  
Heavy Chain

scholarly journals Delineation of the Roles Played by RasG and RasC in cAMP-dependent Signal Transduction during the Early Development of Dictyostelium discoideum

2006 ◽  
Vol 17 (10) ◽  
pp. 4543-4550 ◽  
Author(s):  
Parvin Bolourani ◽  
George B. Spiegelman ◽  
Gerald Weeks
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Dictyostelium Discoideum ◽  
Early Development ◽  
Cell Aggregation ◽  
Early Gene ◽  
Cellular Slime Mold ◽  
Early Gene Expression ◽  
Insertional Inactivation ◽  
Dependent Signal

On starvation, the cellular slime mold Dictyostelium discoideum initiates a program of development leading to formation of multicellular structures. The initial cell aggregation requires chemotaxis to cyclic AMP (cAMP) and relay of the cAMP signal by the activation of adenylyl cyclase (ACA), and it has been shown previously that the Ras protein RasC is involved in both processes. Insertional inactivation of the rasG gene resulted in delayed aggregation and a partial inhibition of early gene expression, suggesting that RasG also has a role in early development. Both chemotaxis and ACA activation were reduced in the rasG− cells, but the effect on chemotaxis was more pronounced. When the responses of rasG− cells to cAMP were compared with the responses of rasC− and rasC−rasG− strains, generated in otherwise isogenic backgrounds, these studies revealed that signal transduction through RasG is more important in chemotaxis and early gene expression, but that signal transduction through RasC is more important in ACA activation. Because the loss of either of the two Ras proteins alone did not result in a total loss of signal output down either of the branches of the cAMP signal-response pathway, there appears to be some overlap of function.

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