Intrasteric Regulation of Myosin Light Chain Kinase

Krueger, Joanna K.; Padre, Roanna C.; Stull, James T.

doi:10.1074/jbc.270.28.16848

Cited by 41 publications

(34 citation statements)

References 33 publications

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“…One region that could participate in c-ABL kinase inhibition is the basic C terminus of AAP1. It has been proposed that a basic motif within MLCK binds to acidic residues in the catalytic core, resulting in autoinhibition (23). The lack of c-ABL kinase inhibition observed with another newly identified ABL SH3-binding protein having a different C-terminal structure further supports this possibility (data not shown).…”

Section: Discussionsupporting

confidence: 70%

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

Zhu

Shore

1996

Molecular and Cellular Biology

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The c-ABL tyrosine kinase is activated following either the loss or mutation of its Src homology domain 3 (SH3), resulting in both increased autophosphorylation and phosphorylation of cellular substrates and cellular transformation. This suggests that the SH3 domain negatively regulates c-ABL kinase activity. For several reasons this regulation is thought to involve a cellular protein that binds to the SH3 domain. Hyperexpression of c-ABL results in an activation of its kinase, the kinase activity of purified c-ABL protein in the absence of cellular proteins is independent of either the presence or absence of a SH3 domain, and point mutations and deletions within the SH3 domain are sufficient to activate c-ABL transforming ability. To identify proteins that interact with the c-ABL SH3 domain, we screened a cDNA library by the yeast two-hybrid system, using the c-ABL SH3SH2 domains as bait. We identified a novel protein, AAP1 (ABL-associated protein 1), that associates with these c-ABL domains and fails to bind to the SH3 domain in the activated oncoprotein BCRABL. Kinase experiments demonstrated that in the presence of AAP1, the ability of c-ABL to phosphorylate either glutathione S-transferase-CRK or enolase was inhibited. In contrast, AAP1 had little effect on the phosphorylation of glutathione S-transferase-CRK by the activated ABL oncoproteins v-ABL and BCRABL. We conclude that AAP1 inhibits c-ABL tyrosine kinase activity but has little effect on the tyrosine kinase activities of oncogenic BCRABL or v-ABL protein and propose that AAP1 functions as a trans regulator of c-ABL kinase. Our data also indicate that loss of susceptibility to AAP1 regulation correlates with oncogenicity of the activated forms of c-ABL.

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Section: Discussionsupporting

confidence: 70%

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

Zhu

Shore

1996

Molecular and Cellular Biology

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“…Autoinhibitory domains of type I cGKs are shown here to involve at least two discrete sequences, a pattern that has been demonstrated in some other protein kinases (62,63). In I␤ cGK, a single arginine, Arg-75, that is part of a putative pseudosubstrate sequence (-74 KRQAI-) in the autoinhibitory domain provides a critical determinant for potent autoinhibition of catalysis, but additional sequences located carboxyl-terminal to this sequence also contribute to autoinhibition.…”

Section: Discussionmentioning

confidence: 97%

Arginine 75 in the Pseudosubstrate Sequence of Type Iβ cGMPdependent Protein Kinase Is Critical for Autoinhibition, Although Autophosphorylated Serine 63 Is Outside This Sequence

Francis

Smith

Colbran

et al. 1996

Journal of Biological Chemistry

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Autoinhibitory domains in many protein kinases include either a phosphorylatable substrate-like sequence or a pseudosubstrate sequence. This study shows that I␤ cGMP-dependent protein kinase (cGK) autophosphorylates Ser-63, which is in an atypical cGK substrate sequence (-59 AQKQSAS-) that is amino-terminal to the pseudosubstrate motif (-74 KRQAI-). cGMP increases the rate of autophosphorylation (ϳ0.8 phosphate/cGK monomer) ϳ3-fold. Autophosphorylation is an intramolecular process since it is independent of cGK concentration. cGMP activation of cGK enhances proteolysis within and near the pseudosubstrate site; treatment of dimeric cGK with three proteases produces three cGK monomers (ϳ67-70 kDa each). Their amino-terminal sequences are 75 RQAISAEPT-, 76 QAISAEPTAF-, and 86 DIQDLSXV-, respectively. cGMP stimulates these kinases by 10-, 2.5-, and 1.4-fold, respectively, compared with a 10-fold effect on intact cGK. Increased basal activity accounts for the diminished stimulation. Thus, the primary autophosphorylation site of I␤ cGK is well outside the pseudosubstrate site, but Arg-75 in the pseudosubstrate site is critical for autoinhibition. Autoinhibition also involves elements that are carboxyl-terminal to Arg-75.

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“…Many CaM regulated kinases, including skMLCK, smMLCK, and MKII, are activated by the removal of an autoinhibitory sequence from the active site of the enzyme, an event that can be triggered either by the binding of CaM to a nearby sequence or by phosphorylation of key residues (Zurini et al, 1984;Edelman et al, 1985;Pearson et al, 1988;Olson et al, 1990;Gallagher et al, 1993;Brickey et al, 1994;Krueger et al, 1995;Goldberg et al, 1996). For these proteins, the smaller Ca2+ affinity enhancement observed for the full-size enzyme relative to the isolated target peptide is likely to stem, at least in part, from the energetic cost of removing autoinhibition.…”

Section: Origins Of the Different Tuning Observed For Target Peptidesmentioning

confidence: 99%

Intermolecular tuning of calmodulin by target peptides and proteins: Differential effects on Ca²⁺ binding and implications for kinase activation

1997

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Ca2+-activated calmodulin (CaM) regulates many target enzymes by docking to an amphiphilic target helix of variable sequence. This study compares the equilibrium Ca2+ binding and Ca2+ dissociation kinetics of CaM complexed to target peptides derived from five different CaM-regulated proteins: phosphorylase kinase, CaM-dependent protein kinase 11, skeletal and smooth myosin light chain kinases, and the plasma membrane Ca2+-ATPase. The results reveal that different target peptides can tune the Ca2+ binding affinities and kinetics of the two CaM domains over a wide range of Ca2+ concentrations and time scales. The five peptides increase the Ca2+ affinity of the N-terminal regulatory domain from 14-to 350-fold and slow its Ca2+ dissociation kinetics from 60-to 140-fold. Smaller effects are observed for the C-terminal domain, where peptides increase the apparent Ca2+ affinity 8-to 100-fold and slow dissociation kinetics 13-to 32-fold. In full-length skeletal myosin light chain kinase the inter-molecular tuning provided by the isolated target peptide is further modulated by other tuning interactions, resulting in a CaM-protein complex that has a 10-fold lower Ca2+ affinity than the analogous CaM-peptide complex. Unlike the CaM-peptide complexes, Ca2+ dissociation from the protein complex follows monoexponential kinetics in which all four Ca2+ ions dissociate at a rate comparable to the slow rate observed in the peptide complex. The two Ca2+ ions bound to the CaM N-terminal domain are substantially occluded in the CaM-protein complex. Overall, the results indicate that the cellular activation of myosin light chain kinase is likely to be triggered by the binding of free CaZ2+-CaM or Cq2+-CaM after a Ca2+ signal has begun and that inactivation of the complex is initiated by a single rate-limiting event, which is proposed to be either the direct dissociation of Ca2+ ions from the bound C-terminal domain or the dissociation of Ca2+ loaded C-terminal domain from skMLCK. The observed target-induced variations in Ca2+ affinities and dissociation rates could serve to tune CaM activation and inactivation for different cellular pathways, and also must counterbalance the variable energetic costs of driving the activating conformational change in different target enzymes.Keywords: calcium signaling; calmodulin; kinase regulation; protein-protein interactionsThe ubiquitous protein calmodulin (CaM) plays a crucial role in Ca2+ signaling (Beckingham, 1995;Braun & Schulman, 1995; Clapham, 1995;Wolenski, 1995; Berridge, 1996), where it regulates a wide range of cellular processes by serving as an intracellular receptor for Ca2+ ions (Wheeler et al

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Intrasteric Regulation of Myosin Light Chain Kinase

Cited by 41 publications

References 33 publications

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

Arginine 75 in the Pseudosubstrate Sequence of Type Iβ cGMPdependent Protein Kinase Is Critical for Autoinhibition, Although Autophosphorylated Serine 63 Is Outside This Sequence

Intermolecular tuning of calmodulin by target peptides and proteins: Differential effects on Ca²⁺ binding and implications for kinase activation

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Intrasteric Regulation of Myosin Light Chain Kinase

Cited by 41 publications

References 33 publications

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

c-ABL Tyrosine Kinase Activity Is Regulated by Association with a Novel SH3-Domain-Binding Protein

Arginine 75 in the Pseudosubstrate Sequence of Type Iβ cGMPdependent Protein Kinase Is Critical for Autoinhibition, Although Autophosphorylated Serine 63 Is Outside This Sequence

Intermolecular tuning of calmodulin by target peptides and proteins: Differential effects on Ca2+ binding and implications for kinase activation

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Intermolecular tuning of calmodulin by target peptides and proteins: Differential effects on Ca²⁺ binding and implications for kinase activation