Autoinhibition of Mixed Lineage Kinase 3 through Its Src Homology 3 Domain

Zhang, Hua; Gallo, Kathleen A.

doi:10.1074/jbc.m107176200

Cited by 70 publications

(76 citation statements)

References 41 publications

(43 reference statements)

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“…The binding of the active, small GTPase disrupts this autoinhibitory conformation, resulting in autophosphorylation of the activation loop and activation of PAK (53, 54). Our lab has previously reported that MLK3 is autoinhibited through association of its N-terminal SH3 domain with a sequence containing Pro 469 , which, based at least on primary sequence, is situated in close proximity between the zipper domain (amino acids 400 -462) and the CRIB motif (amino acids 498 -514) (19). Thus although they utilize different structural domains/elements, PAK and MLK3 appear to share a common theme of GTPasemediated disruption of autoinhibition.…”

Section: Discussionmentioning

confidence: 99%

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Cdc42 Induces Activation Loop Phosphorylation and Membrane Targeting of Mixed Lineage Kinase 3

Du¹,

Böck²,

Schachter³

et al. 2005

Journal of Biological Chemistry

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Mixed lineage kinase 3 (MLK3) functions as a mitogen-activated protein kinase kinase kinase to activate multiple mitogen-activated protein kinase pathways. Our current studies demonstrate that lack of MLK3 blocks signaling of activated Cdc42 to c-Jun N-terminal kinase, giving strong support for the idea that Cdc42 is a physiological activator of MLK3. We show herein that Cdc42, in a prenylationdependent manner, targets MLK3 from a perinuclear region to membranes, including the plasma membrane. Cdc42-induced membrane targeting of MLK3 is independent of MLK3 catalytic activity but depends upon an intact Cdc42/Rac-interactive binding motif, consistent with MLK3 membrane translocation being mediated through direct binding of Cdc42. Phosphorylation of the activation loop of MLK3 requires MLK3 catalytic activity and is induced by Cdc42 in a prenylation-independent manner, arguing that Cdc42 binding is sufficient for activation loop autophosphorylation of MLK3. However, membrane targeting is necessary for full activation of MLK3 and maximal signaling to JNK. We previously reported that MLK3 is autoinhibited through an interaction between its N-terminal SH3 domain and a proline-containing sequence found between the leucine zipper and the CRIB motif of MLK3. Thus we propose a model in which GTP-bound Cdc42/Rac binds MLK3 and disrupts SH3-mediated autoinhibition leading to dimerization and activation loop autophosphorylation. Targeting of this partially active MLK3 to membranes likely results in additional phosphorylation events that fully activate MLK3 and its ability to maximally signal through the JNK pathway.

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Section: Discussionmentioning

confidence: 99%

“…Zipper-mediated homo-oligomerization is required for full activity of MLK3, proper substrate phosphorylation, and activation of the JNK pathway (17,18). Work from our lab indicates that MLK3 is autoinhibited through an interaction between its SH3 domain and a proline-containing sequence within MLK3 (19).…”

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confidence: 99%

Cdc42 Induces Activation Loop Phosphorylation and Membrane Targeting of Mixed Lineage Kinase 3

Du¹,

Böck²,

Schachter³

et al. 2005

Journal of Biological Chemistry

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“…8 The SH3 domain of MLK3 can bind a proline residue in a region between the leucine zipper and the CRIB motif resulting in autoinhibition. 9 Overexpression of Cdc42 has been shown to induce activation of MLK3 and this activation requires the MLK3 CRIB motif. 7,10 It has been proposed that binding of GTP-bound Rac or Cdc42 to MLK3 through the CRIB motif could disrupt the autoinhibitory interaction and allow MLK3 kinase activation.…”

Section: Introductionmentioning

confidence: 99%

A Novel Role for Mixed Lineage Kinase 3 (MLK3) in B-Raf Activation and Cell proliferation

Chadee¹,

Kyriakis²

2004

Cell Cycle

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Once the issue is complete and page numbers have been assigned, the citation will change accordingly. KEY WORDS MLK3, cell proliferation, MAP kinase, B-Raf, EGF ABBREVIATIONS CRIB A Novel Role for Mixed Lineage Kinase 3 (MLK3) in B-Raf Activation and Cell Proliferation ABSTRACTThe extracellular signal-regulated kinase (ERK) group of MAPKs is essential for cell proliferation, including that stimulated by mitogens, oncogenic ras and raf. The Raf kinases (especially B-Raf) are ERK-specific, mitogen-activated MAP3Ks. Mixed lineage kinase-3 (MLK3) is a MAP3K previously thought to be a selective regulator of the JNK group of MAPKs. Surprisingly, we found that silencing of mlk3 by RNAi suppresses mitogen and cytokine activation not only of JNK but of ERK and p38 as well. Silencing mlk3 also blocks mitogen-stimulated phosphorylation of B-Raf at Thr598 and Ser601-a step required for B-Raf activation. Finally, silencing mlk3 prevents serum-stimulated cell proliferation and the proliferation of tumor cells bearing either oncogenic Ki-Ras or loss of function neurofibromatosis-1 (NF1) or NF2 mutations. The proliferation of tumor cells with activating mutations in B-raf or raf-1 are unaffected by silencing mlk3. These results define a new role for MLK3 in B-Raf activation, ERK signaling and cell proliferation. Accordingly, targeting MLK3 could be beneficial to the treatment of tumors with activated receptor tyrosine kinase or ras mutations, and to the treatment of NF1 or NF2 tumors.Mammalian mitogen-activated protein kinase (MAPK) signaling cascades function to integrate and transmit signals from the cell surface to the nucleus resulting in the regulation of specific gene expression. A common feature of MAPK signaling is a three-tiered core signaling module in which MAPKs are activated by Tyr and Thr phosphorylation that is catalyzed by MAPK kinases (MKKs) which are in turn phosphorylated on Ser and Thr residues by MAPK kinase kinases (MAP3Ks). 1 To date, many MAP3Ks have been identified that respond to a wide range of extracellular stimuli and relay specific signals to a relatively small number of downstream MKKs. The mechanism of regulation of the MAP3Ks by upstream activators and extracellular stimuli remains an area of intense study and the biological function of many of these enzymes have yet to be elucidated.MLK3 (mixed lineage kinase 3) is a MAP3K that was shown to specifically activate the MKKs, MKK4 and MKK3, which in turn activate the Jun N-terminal kinase (JNK) and p38 pathways, respectively. 2,3 Overexpression of MLK3 has also been reported to activate NF-κB. 4 Extracellular stimuli that activate MLK3 include tumor necrosis factor alpha (TNFα), ceramide and engagement of the T-cell receptor by costimulation with anti-CD3 and anti-CD28 antibodies. 4,5 Upstream activators of MLK3 include Cdc42 and germinal center kinase. 6,7 MLK3 contains an amino-terminal Src-homology 3 (SH3) domain, a kinase domain, a leucine zipper and a Cdc42/Rac interactive binding (CRIB) motif. MLK3 can dimerize through its leucine zippers an...

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“…A point mutation (Y52A) in the SH3 domain-binding site of MLK3 abolishes binding to the SH3 domain and increases the MLK3 activity (43). The Y52A mutant shows a 2-fold increase in autophosphorylation and a 2.5-fold increase in histone phosphorylation.…”

Section: Discussionmentioning

confidence: 99%

Mutational Analysis of Stress-responsive Peanut Dual Specificity Protein Kinase

Rudrabhatla

Rajasekharan

2003

Journal of Biological Chemistry

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We recently reported that Arachis hypogaea serine/ threonine/tyrosine (STY) protein kinase is developmentally regulated and is induced by abiotic stresses (Rudrabhatla, P., and Rajasekharan, R. (2002 Tyrosine phosphorylation plays an important role in the regulation of many cellular processes. The activity of the enzymes governing this modification, protein-tyrosine kinases and phosphatases, needs to be tightly controlled for tyrosine phosphorylation to proceed in an orderly manner. Improper phosphorylation due to malfunction of protein-tyrosine kinases and phosphatases can lead to diseases in humans and animals, including immunodeficiencies and cancer (1). In higher plants, several serine/threonine kinases have been identified, but the presence of protein-tyrosine kinases remains controversial. No tyrosine kinase has hitherto been cloned from plants. However, tyrosine phosphorylation in plants has been shown to be involved in various physiological processes (2-4). Dual specificity protein kinases have been reported in Arabidopsis (5, 6) and soybean (7), but the functions for these kinases remain unknown. We recently reported that serine/threonine/tyrosine (STY) 1 protein kinase from Arachis hypogaea is developmentally regulated and induced by abiotic stress (8). The site of tyrosine phosphorylation has not been identified for any dual specificity protein kinases in plants. However, MAPKs have been shown to be activated by dual phosphorylation of threonine and tyrosine in the Thr-Glu-Tyr (TEY) motif in the activation loop (9). Recently, the role of threonines in the phosphorylation of receptor-like kinase has been identified in plants (10,11).Most protein kinases retain their kinase domain conserved sequence motifs, which are separated into subdomains I-XI. The region between the conserved DFG sequence motif in subdomain VII and the APE sequence motif in subdomain VIII is referred to as the activation loop. Several protein kinases such as cAMP-dependent protein kinase (12), a MAPK family (13), a MAPK kinase (MEK) family (14, 15), a cyclin-dependent protein kinase family (16), and c-Src tyrosine kinase (17) are activated by phosphorylation of residues within the activation loop (18). Phosphorylation negatively regulates a substantial number of protein kinases. For example, phosphorylation of cyclin-dependent protein kinase at threonine and tyrosine residues in the ATP-binding loop by wee1-related kinases leads to kinase inactivation (16), and phosphorylation of the Src tyrosine kinase at a tyrosine residue in the C terminus maintains the kinase in an inactive conformation (18).Here we report a novel site of autoinhibition of STY protein kinase. In contrast to the above-mentioned kinases, we demonstrate here that the phosphorylation of Tyr 148 in the ATPbinding domain and of Tyr 317 in the C-terminal domain activates STY protein kinase. The replacement of Tyr 297 with Phe in the activation loop resulted in a drastic reduction in the phosphorylation of peanut STY protein kinase with ATP and histone. This study prov...

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Autoinhibition of Mixed Lineage Kinase 3 through Its Src Homology 3 Domain

Cited by 70 publications

References 41 publications

Cdc42 Induces Activation Loop Phosphorylation and Membrane Targeting of Mixed Lineage Kinase 3

Cdc42 Induces Activation Loop Phosphorylation and Membrane Targeting of Mixed Lineage Kinase 3

A Novel Role for Mixed Lineage Kinase 3 (MLK3) in B-Raf Activation and Cell proliferation

Mutational Analysis of Stress-responsive Peanut Dual Specificity Protein Kinase

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