scholarly journals Identification of a Protein Kinase fromDictyosteliumwith Homology to the Novel Catalytic Domain of Myosin Heavy Chain Kinase A

1997 ◽  
Vol 272 (18) ◽  
pp. 11812-11815 ◽  
Author(s):  
Colleen E. Clancy ◽  
Manual G. Mendoza ◽  
Teresa V. Naismith ◽  
Michael F. Kolman ◽  
Thomas T. Egelhoff
1997 ◽  
Vol 272 (11) ◽  
pp. 6846-6849 ◽  
Author(s):  
Graham P. Côté ◽  
Xia Luo ◽  
Michael B. Murphy ◽  
Thomas T. Egelhoff

2004 ◽  
Vol 280 (4) ◽  
pp. 2879-2887 ◽  
Author(s):  
Thomas T. Egelhoff ◽  
Daniel Croft ◽  
Paul A. Steimle

2006 ◽  
Vol 395 (2) ◽  
pp. 373-383 ◽  
Author(s):  
Misty Russ ◽  
Daniel Croft ◽  
Omar Ali ◽  
Raquel Martinez ◽  
Paul A. Steimle

Myosin heavy-chain kinase A (MHCK A) catalyses the disassembly of myosin II filaments in Dictyostelium cells via myosin II heavy-chain phosphorylation. MHCK A possesses a ‘coiled-coil’-enriched domain that mediates the oligomerization, cellular localization and actin-binding activities of the kinase. F-actin (filamentous actin) binding by the coiled-coil domain leads to a 40-fold increase in MHCK A activity. In the present study we examined the actin-binding characteristics of the coiled-coil domain as a means of identifying mechanisms by which MHCK A-mediated disassembly of myosin II filaments can be regulated in the cell. Co-sedimentation assays revealed that the coiled-coil domain of MHCK A binds co-operatively to F-actin with an apparent KD of approx. 0.5 μM and a stoichiometry of approx. 5:1 [actin/C(1–498)]. Further analyses indicate that the coiled-coil domain binds along the length of the actin filament and possesses at least two actin-binding regions. Quite surprisingly, we found that the coiled-coil domain cross-links actin filaments into bundles, indicating that MHCK A can affect the cytoskeleton in two important ways: (1) by driving myosin II-filament disassembly via myosin II heavy-chain phosphorylation, and (2) by cross-linking/bundling actin filaments. This discovery, along with other supporting data, suggests a model in which MHCK A-mediated bundling of actin filaments plays a central role in the recruitment and activation of the kinase at specific sites in the cell. Ultimately this provides a means for achieving the robust and highly localized disruption of myosin II filaments that facilitates polarized changes in cell shape during processes such as chemotaxis, cytokinesis and multicellular development.


2010 ◽  
Vol 3 (111) ◽  
pp. ra17-ra17 ◽  
Author(s):  
Q. Ye ◽  
S. W. Crawley ◽  
Y. Yang ◽  
G. P. Cote ◽  
Z. Jia

1995 ◽  
Vol 270 (2) ◽  
pp. 523-529 ◽  
Author(s):  
Lidia M. Futey ◽  
Quintus G. Medley ◽  
Graham P. Côté ◽  
Thomas T. Egelhoff

2002 ◽  
Vol 13 (12) ◽  
pp. 4333-4342 ◽  
Author(s):  
Akira Nagasaki ◽  
Go Itoh ◽  
Shigehiko Yumura ◽  
Taro Q.P. Uyeda

We have cloned a full-length cDNA encoding a novel myosin II heavy chain kinase (mhckC) from Dictyostelium. Like other members of the myosin heavy chain kinase family, themhckC gene product, MHCK C, has a kinase domain in its N-terminal half and six WD repeats in the C-terminal half. GFP-MHCK C fusion protein localized to the cortex of interphase cells, to the cleavage furrow of mitotic cells, and to the posterior of migrating cells. These distributions of GFP-MHCK C always corresponded with that of myosin II filaments and were not observed in myosin II-null cells, where GFP-MHCK C was diffusely distributed in the cytoplasm. Thus, localization of MHCK C seems to be myosin II-dependent. Cells lacking the mhckC gene exhibited excessive aggregation of myosin II filaments in the cleavage furrows and in the posteriors of the daughter cells once cleavage was complete. The cleavage process of these cells took longer than that of wild-type cells. Taken together, these findings suggest MHCK C drives the disassembly of myosin II filaments for efficient cytokinesis and recycling of myosin II that occurs during cytokinesis.


2002 ◽  
Vol 283 (1) ◽  
pp. H213-H219 ◽  
Author(s):  
Qianxun Xiao ◽  
Agnes Kenessey ◽  
Kaie Ojamaa

Contractile activity of the cardiac myocyte is required for maintaining cell mass and phenotype, including expression of the cardiac-specific α-myosin heavy chain (α-MHC) gene. An E-box hemodynamic response element (HME) located at position −47 within the α-MHC promoter is both necessary and sufficient to confer contractile responsiveness to the gene and has been shown to bind upstream stimulatory factor-1 (USF1). When studied in spontaneously contracting cardiac myocytes, there is enhanced binding of USF1 to the HME compared with quiescent cells, which correlates with a threefold increase in α-MHC promoter activity. A molecular mechanism by which contractile function modulates α-MHC transcriptional activity may involve signaling via phosphorylation of USF1. The present studies showed that purified rat USF1 was phosphorylated in vitro by protein kinase C (PKC) and cAMP-dependent protein kinase (PKA) but not casein kinase II. Phosphorylated USF1 by either PKC or PKA had increased DNA binding activity to the HME. PKC-mediated phosphorylation also leads to the formation of USF1 multimers as assessed by gel shift assay. Analysis of in vivo phosphorylated nuclear proteins from cultured ventricular myocytes showed that USF1 was phosphorylated, and resolution by two-dimensional gel electrophoresis identified at least two distinct phosphorylated USF1 molecules. These results suggest that endogenous kinases can covalently modify USF1 and provide a potential molecular mechanism by which the contractile stimulus mediates changes in myocyte gene transcription.


Sign in / Sign up

Export Citation Format

Share Document