Inhibitor κB Kinase

Abstract

At a recent Grand Rounds presentation, the topic of discussion was introduced as regarding “…the most important muscle of the body that nobody knows about.” Although it is clear to clinicians and physiologists that smooth muscle controls the dimensions of nearly all hollow organs of the body, and that alterations in this control system participate in diverse and debilitating disorders such as hypertension, vasospasm, vasodilatory shock, asthma, overactive bladder, and irritable bowel syndrome, the muscle type that has garnered the majority of the limelight for generations has cross-striations. Article, see p 562 No single reason can explain smooth muscle’s limited exposition in general textbooks to account for its apparent second-class status behind striated muscle. However, a goal of science is to clarify by reduction, whereas complexity only recently has been embraced, leading to newer disciplines, such as systems biology. Studies during the past 40 years certainly indicate that smooth muscles display astounding complexity and diversity in biomechanical behavior and in regulation of contractile protein activation. Regarding the latter, the study by Ying et al1 in this issue of Circulation Research has added one more kinase to a growing number of regulatory proteins known to play a role in causing smooth muscle contraction. More than 100 years ago, Ringer2 showed that calcium was required for heart contraction. Calcium and the thin filament protein troponin are the central players in the regulation of striated muscle contraction, permitting active myosin from continuing through its actomyosin cross-bridge …