Polarization of myosin II heavy chain-protein kinase C in chemotaxing dictyostelium cells.
Eukaryotic cells need morphological polarity to carry out chemotaxis (Parent, C. A., Blacklock, B. J., Froehlich, W. M., Murphy, D. B., and Devreotes, P. N. (1998) Cell 95, 81-91; Jin, T., Zhang, N., Long, Y., Parent, C., and Devreotes, P. N. (2000) Science 287, 1034-1036; Servant, G., Weiner, O. D., Herzmark, P., Balla, T., Sedat, J. W., and Bourne, H. R. (2000) Science 287, 1037-1040), but sensing direction does not require polarization of chemoattractant receptors. When cells are exposed to a gradient of chemoattractant, activation occurs selectively at the stimulated edge. Such localized activation, transmitted by the recruitment of cytosolic proteins, may be a general mechanism for gradient sensing by G protein-linked chemotactic systems. Here we show that in Dictyostelium discoideum cells exposed to a cAMP gradient the myosin II heavy chain kinase (MHC-PKC) and myosin II translocate to opposite ends of the cell. We further show that MHC-PKC C1 domain is responsible for the localization of MHC-PKC to the cell leading edge, but it is not sufficient to promote cell polarization. Our findings suggest a mechanism by which MHC-PKC regulates myosin II, allowing cell polarization and movement in the direction of the cAMP source.
Department of Biochemistry, Hadassah Medical School, Institute of Medical Sciences, The Hebrew University, Jerusalem 91120, Israel.
Hila
H
Rubin
Shoshana
S
Ravid
D000818:Animals; D015153:Blotting, Western; D002633:Chemotaxis; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004023:Dictyostelium; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D024462:Myosin Type II / Q000737:chemistry* / Q000378:metabolism; D011493:Protein Kinase C / Q000737:chemistry* / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000242:Cyclic AMP; D011493:Protein Kinase C; D024462:Myosin Type II