ISSN:
0886-1544
Keywords:
myosin II
;
cardiac
;
sarcomeric
;
cytoplasmic myosin
;
LMM
;
Dd
;
heterologous expression
;
ConA
;
receptor capping
;
aggregation
;
filament assembly region
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Manipulation of the single conventional myosin heavy chain (mhc) gene in Dictyostelium discoideum (Dd) has delineated an essential role for the filament-forming, or light meromyosin (LMM) domain of the myosin molecule in cyto-kinesis, development, and in the capping of cell surface receptors (see Spudich: Cell Regulation 1:1-11, 1989; Egelhoff et al.: Journal of Cell Biology, 112:677-688, 1991a). In order to assess the functional relationship between sarcomeric and cytoplasmic myosins, a chimeric gene encoding the Dd myosin head and subfragment 2 fused to rat β cardiac LMM was transfected into both wild-type and Dd mhc null cells. Chimeric myosin was organized into dense cortical patches in the cytoplasm of both wild-type and Dd mhc null cells. Although null cells expressing chimeric mhc at ∼10% of Dd mhc levels were unable to grow in shaking suspension or to complete development, chimeric myosin was able to rescue capping of cell surface receptors, to associate with filamentous actin, and to localize to the correct subcellular position during aggregation. Deletion of 29 amino acids in the rod corresponding to a previously defined filament assembly competent region eliminated the cortical patches and the posterior localization during chemotaxis. Taken together, these observations suggest that sarcomeric and cytoplasmic myosin rods are functionally interchangeable in several aspects of nonmuscle motility. © 1994 Wiley-Liss, Inc.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cm.970270404
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