Defining smooth muscle cells and smooth muscle injury.
For 3 decades, terms such as synthetic phenotype and contractile phenotype have been used to imply the existence of a specific mechanism for smooth muscle cell (SMC) responses to injury. In this issue of the JCI, Hendrix et al. offer a far more precise approach to examining the mechanisms of SMC responses to injury, focused not on general changes in phenotype but on effects of injury on a single promoter element, the CArG [CC(A/T)6GG] box, in a single gene encoding smooth muscle (SM) alpha-actin. Since CArG box structures are present in some, but not all, SMC genes, these data suggest that we may be progressing toward establishing a systematic, molecular classification of both SMC subsets and the response of SMCs to different injuries.
Mahoney
William M
WM
Department of Pathology, University of Washington, Seattle, Washington 98195-7335, USA.
Schwartz
Stephen M
SM
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D006801:Humans; D009130:Muscle, Smooth / Q000473:pathology* / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics
D000199:Actins