Myosin heavy chain kinases play essential roles in Ca2+, but not cAMP, chemotaxis and the natural aggregation of Dictyostelium discoideum.
Behavioral analyses of the deletion mutants of the four known myosin II heavy chain (Mhc) kinases of Dictyostelium discoideum revealed that all play a minor role in the efficiency of basic cell motility, but none play a role in chemotaxis in a spatial gradient of cAMP generated in vitro. However, the two kinases MhckA and MhckC were essential for chemotaxis in a spatial gradient of Ca(2+), shear-induced directed movement, and reorientation in the front of waves of cAMP during natural aggregation. The phenotypes of the mutants mhckA(-) and mhckC(-) were highly similar to that of the Ca(2+) channel/receptor mutant iplA(-) and the myosin II phosphorylation mutant 3XALA, which produces constitutively unphosphorylated myosin II. These results demonstrate that IplA, MhckA and MhckC play a selective role in chemotaxis in a spatial gradient of Ca(2+), but not cAMP, and suggest that Ca(2+) chemotaxis plays a role in the orientation of cells in the front of cAMP waves during natural aggregation.
Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, 52242, USA.
Deborah
D
Wessels
Daniel F
DF
Lusche
Paul A
PA
Steimle
Amanda
A
Scherer
Spencer
S
Kuhl
Kristen
K
Wood
Brett
B
Hanson
Thomas T
TT
Egelhoff
David R
DR
Soll
D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D002449:Cell Aggregation / Q000235:genetics; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006801:Humans; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism; D017384:Sequence Deletion
D015800:Protozoan Proteins; D000242:Cyclic AMP; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C033142:myosin-heavy-chain kinase; D018995:Myosin Heavy Chains; D002118:Calcium