Learn More
We present a current perception of the regulation of activation of cardiac myofilaments with emphasis on troponin (Tn) and tropomyosin (Tm). Activation involves both a Ca2+-regulated molecular switch and a potentiated state, dependent on feedback effects of force-generating crossbridges. Recent developments in the elucidation of the structure and(More)
Heterotrimeric GTP-binding proteins (G proteins) regulate cellular activity by coupling to hormone or sensory receptors. Stimulated receptors catalyse the release of GDP from G protein alpha-subunits and GTP bound to the empty alpha-subunits provides signals that control effectors such as adenylyl cyclases, phosphodiesterases, phospholipases and ion(More)
The N-terminal region of skeletal myosin light chain-1 (MLC-1) binds to the C terminus of actin, yet the functional significance of this interaction is unclear. We studied a fragment (MLC-pep; residues 5-14) of the ventricular MLC-1. When added to rat cardiac myofibrils, 10 nM MLC-pep induced a supramaximal increase in the MgATPase activity at submaximal(More)
In photoreceptor cells of vertebrates light activates a series of protein-protein interactions resulting in activation of a cGMP-phosphodiesterase (PDE). Interaction between the GTP-bound form of rod G-protein alpha-subunit (alpha t) and PDE inhibitory gamma-subunit (P gamma) is a key event for effector enzyme activation. This interaction has been studied(More)
Although the C terminus of troponin I is known to be important in myofilament Ca2+ regulation in skeletal muscle, the regulatory function of this region of cardiac troponin I (cTnI) has not been defined. To address this question, the following recombinant proteins were expressed in Escherichia coli and purified: mouse wild-type cTnI (WT cTnI; 211 residues),(More)
The heterotrimeric guanine nucleotide binding proteins (G proteins) are activated by sensory or hormone receptors. In turn, the G proteins activate effector proteins such as adenylyl cyclase, cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP PDE), phospholipase C, and potassium and calcium ion channels by mechanisms that are poorly understood. A(More)
Cardiac troponin I (cTnI) is an essential element in activation of myofilaments by Ca2+ binding to cardiac troponin C (cTnC). Yet, its role in transduction of the Ca2+ binding signal to cardiac troponin T (cTnT) and tropomyosin-actin remain poorly understood. We have recently discovered that regions of cTnI C-terminal to a previously defined inhibitory(More)
The molecular basis of the interaction between the visual receptor, rhodopsin, and the rod outer segment GTP-binding protein, transducin or Gt, was studied using a synthetic-peptide-competition approach to elucidate the site(s) on the Gt alpha-subunit (alpha t) involved in high-affinity binding to light-activated rhodopsin (R*). Synthetic peptides based on(More)
  • 1