scholarly journals The LxVP and PxIxIT NFAT Motifs Bind Jointly to Overlapping Epitopes on Calcineurin’s Catalytic Domain Distant to the Regulatory Domain

Structure ◽  
2014 ◽  
Vol 22 (7) ◽  
pp. 1016-1027 ◽  
Author(s):  
Maayan Gal ◽  
Shuai Li ◽  
Rafael E. Luna ◽  
Koh Takeuchi ◽  
Gerhard Wagner
1992 ◽  
Vol 76 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Nobutaka Minami ◽  
Eiichi Tani ◽  
Yukio Maeda ◽  
Ikuya Yamaura ◽  
Masahiro Fukami

✓ Vasospasm was produced in adult mongrel dogs by a two-hemorrhage method, and the spastic basilar arteries were exposed via the transclival route on Day 7. Tonic contraction was produced in the normal canine basilar arteries by a local application of KCl or serotonin after transclival exposure. The exposed spastic and tonic basilar arteries then received a topical application of the following: 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H-7), a potent inhibitor of protein kinase C acting at the catalytic domain; calphostin C, a specific inhibitor of protein kinase C acting at the regulatory domain; or calpeptin, a selective inhibitor of calpain. Both spastic and tonic basilar arteries were effectively dilated by H-7. Calphostin C caused only slight dilation of spastic basilar arteries but moderate dilation of tonic basilar arteries. Dilation in response to calpeptin was remarkable in the spastic basilar arteries but slight in the tonic basilar arteries. The doses of calphostin C and calpeptin required to obtain maximum effect were markedly lower in the tonic model than in the spastic model. The spastic and tonic models had a similar dose-dependent response to H-7 but quite a different response to calphostin C or calpeptin, suggesting a difference in the function of protein kinase C and calpain in the two models. Furthermore, the effect of calphostin C on the reversal of vasospasm was increased significantly after topical treatment with calpeptin. It is suggested that the majority of the catalytic domain of protein kinase C is dissociated from the regulatory domain, probably by a limited proteolysis with calpain, and is markedly activated in vasospasm.


1999 ◽  
Vol 19 (1) ◽  
pp. 602-611 ◽  
Author(s):  
Hua Tu ◽  
Mike Wigler

ABSTRACT Pak1 protein kinase of Schizosaccharomyces pombe, a member of the p21-GTPase-activated protein kinase (PAK) family, participates in signaling pathways including sexual differentiation and morphogenesis. The regulatory domain of PAK proteins is thought to inhibit the kinase catalytic domain, as truncation of this region renders kinases more active. Here we report the detection in the two-hybrid system of the interaction between Pak1 regulatory domain and the kinase catalytic domain. Pak1 catalytic domain binds to the same highly conserved region on the regulatory domain that binds Cdc42, a GTPase protein capable of activating Pak1. Two-hybrid, mutant, and genetic analyses indicated that this intramolecular interaction rendered the kinase in a closed and inactive configuration. We show that Cdc42 can induce an open configuration of Pak1. We propose that Cdc42 interaction disrupts the intramolecular interactions of Pak1, thereby releasing the kinase from autoinhibition.


1999 ◽  
Vol 145 (4) ◽  
pp. 713-726 ◽  
Author(s):  
Ruth Zeidman ◽  
Bjarne Löfgren ◽  
Sven Påhlman ◽  
Christer Larsson

To investigate the role of protein kinase C (PKC) isoforms in regulation of neurite outgrowth, PKCα, βII, δ, and ε fused to enhanced green fluorescent protein (EGFP) were transiently overexpressed in neuroblastoma cells. Overexpression of PKCε–EGFP induced cell processes whereas the other isoforms did not. The effect of PKCε–EGFP was not suppressed by the PKC inhibitor GF109203X. Instead, process formation was more pronounced when the regulatory domain was introduced. Overexpression of various fragments from PKCε regulatory domain revealed that a region encompassing the pseudosubstrate, the two C1 domains, and parts of the V3 region were necessary and sufficient for induction of processes. By deleting the second C1 domain from this construct, a dominant-negative protein was generated which suppressed processes induced by full-length PKCε and neurites induced during retinoic acid- and growth factor–induced differentiation. As with neurites in differentiated neuroblastoma cells, processes induced by the PKCε– PSC1V3 protein contained α-tubulin, neurofilament-160, and F-actin, but the PKCε–PSC1V3-induced processes lacked the synaptic markers synaptophysin and neuropeptide Y.  These data suggest that PKCε, through its regulatory domain, can induce immature neurite-like processes via a mechanism that appears to be of importance for neurite outgrowth during neuronal differentiation.


2003 ◽  
Vol 373 (2) ◽  
pp. 571-581 ◽  
Author(s):  
Angie F. KIRWAN ◽  
Ashley C. BIBBY ◽  
Thierry MVILONGO ◽  
Heimo RIEDEL ◽  
Thomas BURKE ◽  
...  

The N-terminal pseudosubstrate site within the protein kinase Cα (PKCα)-regulatory domain has long been regarded as the major determinant for autoinhibition of catalytic domain activity. Previously, we observed that the PKC-inhibitory capacity of the human PKCα-regulatory domain was only reduced partially on removal of the pseudosubstrate sequence [Parissenti, Kirwan, Kim, Colantonio and Schimmer (1998) J. Biol. Chem. 273, 8940–8945]. This finding suggested that one or more additional region(s) contributes to the inhibition of catalytic domain activity. To assess this hypothesis, we first examined the PKC-inhibitory capacity of a smaller fragment of the PKCα-regulatory domain consisting of the C1a, C1b and V2 regions [GST-Rα39–177: this protein contained the full regulatory domain of human PKCα fused to glutathione S-transferase (GST), but lacked amino acids 1–38 (including the pseudosubstrate sequence) and amino acids 178–270 (including the C2 region)]. GST-Rα39–177 significantly inhibited PKC in a phorbol-independent manner and could not bind the peptide substrate used in our assays. These results suggested that a region within C1/V2 directly inhibits catalytic domain activity. Providing further in vivo support for this hypothesis, we found that expression of N-terminally truncated pseudosubstrate-less bovine PKCα holoenzymes in yeast was capable of inhibiting cell growth in a phorbol-dependent manner. This suggested that additional autoinhibitory force(s) remained within the truncated holoenzymes that could be relieved by phorbol ester. Using tandem PCR-mediated mutagenesis, we observed that mutation of amino acids 33–86 within GST-Rα39–177 dramatically reduced its PKC-inhibitory capacity when protamine was used as substrate. Mutagenesis of a broad range of sequences within C2 (amino acids 159–242) also significantly reduced PKC-inhibitory capacity. Taken together, these observations support strongly the existence of multiple regions within the PKCα-regulatory domain that play a direct role in the inhibition of catalytic domain activity.


1991 ◽  
Vol 276 (1) ◽  
pp. 257-260 ◽  
Author(s):  
C Pears ◽  
D Schaap ◽  
P J Parker

Protein kinase C (PKC) consists of a family of closely related enzymes that can be divided into two subfamilies (alpha, beta and gamma and delta, epsilon and zeta) on the basis of primary sequence. Functional differences have also been described; thus PKC-alpha, PKC-beta and PKC-gamma readily phosphorylate histone IIIS in vitro, whereas PKC-epsilon will not employ this substrate efficiently. We have previously demonstrated, however, that proteolytic cleavage of PKC-epsilon generates a constitutive kinase activity that is an efficient histone IIIS kinase [Schaap, Hsuan, Totty & Parker (1990) Eur. J. Biochem. 191, 431-435]. In order to investigate the structural basis for this switch in specificity, we have constructed a chimaeric protein containing the regulatory domain of PKC-epsilon fused to the catalytic domain of PKC-gamma. When this is expressed in COS1 cells the chimaeric kinase shows a substrate-specificity similar to that of PKC-epsilon rather than to that of PKC-gamma. This demonstrates a role for the regulatory domain in substrate selection of PKC-epsilon.


1997 ◽  
Vol 17 (10) ◽  
pp. 5876-5887 ◽  
Author(s):  
H Tu ◽  
M Barr ◽  
D L Dong ◽  
M Wigler

Byr2 protein kinase, a homolog of mammalian mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEKK) and Saccharomyces cerevisiae STE11, is required for pheromone-induced sexual differentiation in the fission yeast Schizosaccharomyces pombe. Byr2 functions downstream of Ste4, Ras1, and the membrane-associated receptor-coupled heterotrimeric G-protein alpha subunit, Gpa1. Byr2 has a distinctive N-terminal kinase regulatory domain and a characteristic C-terminal kinase catalytic domain. Ste4 and Ras1 interact with the regulatory domain of Byr2 directly. Here, we define the domains of Byr2 that bind Ste4 and Ras1 and show that the Byr2 regulatory domain binds to the catalytic domain in the two-hybrid system. Using Byr2 mutants, we demonstrate that these direct physical interactions are all required for proper signaling. In particular, the physical association between Byr2 regulatory and catalytic domains appears to result in autoinhibition, the loss of which results in kinase activation. Furthermore, we provide evidence that Shk1, the S. pombe homolog of the STE20 protein kinase, can directly antagonize the Byr2 intramolecular interaction, possibly by phosphorylating Byr2.


2013 ◽  
Vol 454 (1) ◽  
pp. 13-30 ◽  
Author(s):  
Peter H. Sugden ◽  
Liam J. McGuffin ◽  
Angela Clerk

The GCKIII (germinal centre kinase III) subfamily of the mammalian Ste20 (sterile 20)-like group of serine/threonine protein kinases comprises SOK1 (Ste20-like/oxidant-stress-response kinase 1), MST3 (mammalian Ste20-like kinase 3) and MST4. Initially, GCKIIIs were considered in the contexts of the regulation of mitogen-activated protein kinase cascades and apoptosis. More recently, their participation in multiprotein heterocomplexes has become apparent. In the present review, we discuss the structure and phosphorylation of GCKIIIs and then focus on their interactions with other proteins. GCKIIIs possess a highly-conserved, structured catalytic domain at the N-terminus and a less-well conserved C-terminal regulatory domain. GCKIIIs are activated by tonic autophosphorylation of a T-loop threonine residue and their phosphorylation is regulated primarily through protein serine/threonine phosphatases [especially PP2A (protein phosphatase 2A)]. The GCKIII regulatory domains are highly disorganized, but can interact with more structured proteins, particularly the CCM3 (cerebral cavernous malformation 3)/PDCD10 (programmed cell death 10) protein. We explore the role(s) of GCKIIIs (and CCM3/PDCD10) in STRIPAK (striatin-interacting phosphatase and kinase) complexes and their association with the cis-Golgi protein GOLGA2 (golgin A2; GM130). Recently, an interaction of GCKIIIs with MO25 has been identified. This exhibits similarities to the STRADα (STE20-related kinase adaptor α)–MO25 interaction (as in the LKB1–STRADα–MO25 heterotrimer) and, at least for MST3, the interaction may be enhanced by cis-autophosphorylation of its regulatory domain. In these various heterocomplexes, GCKIIIs associate with the Golgi apparatus, the centrosome and the nucleus, as well as with focal adhesions and cell junctions, and are probably involved in cell migration, polarity and proliferation. Finally, we consider the association of GCKIIIs with a number of human diseases, particularly cerebral cavernous malformations.


1992 ◽  
Vol 116 (4) ◽  
pp. 863-874 ◽  
Author(s):  
G James ◽  
E Olson

Members of the protein kinase C (PKC) family are characterized by an NH2-terminal regulatory domain containing binding sites for calcium, phosphatidylserine, and diacylglycerol (or tumor-promoting phorbol esters), a small central hinge region and a COOH-terminal catalytic domain. We have constructed fusion proteins in which the regulatory domain of PKC alpha was removed and replaced by a 19-amino acid leader sequence containing a myristoylation consensus or by the same sequence in which the amino-terminal glycine was changed to alanine to prevent myristoylation. The goal was to generate constitutively active mutants of PKC that were either membrane bound, due to their myristoylation, or cytoplasmic. Western blotting of fractions from COS cells transfected with plasmids encoding wild-type and mutant proteins revealed that PKC alpha resided entirely in a Triton X-100 soluble (TS) fraction, whereas both the myristoylated and nonmyristoylated mutants were associated primarily with the nuclear envelope fraction. A similar mutant that lacked the 19 amino acid leader sequence was also found almost entirely in the nuclear envelope, as was a truncation mutant containing only the regulatory domain, hinge region, and a small portion of the catalytic domain. However, an additional truncation mutant consisting of only the regulatory domain plus the first one-third of the hinge region was almost entirely in the TS fraction. A nonmyristoylated fusion protein containing only the catalytic domain was also found in the nuclear envelope. Immunostaining of cells transfected with these constructs revealed that both the myristoylated and nonmyristoylated mutants were localized in nuclei, whereas wild-type PKC alpha was primarily cytoplasmic and perinuclear. Phorbol dibutyrate treatment of PKC alpha-transfected cells resulted in increased perinuclear and nuclear staining. The results are consistent with a model in which activation of PKC, by phorbol esters or by deletion of the regulatory domain, exposes regions in the hinge and catalytic domains that interact with a PKC "receptor" present in the nuclear envelope, and may explain the ability of wild-type PKC to be translocated to the nucleus under certain conditions.


2019 ◽  
Vol 476 (7) ◽  
pp. 1037-1051 ◽  
Author(s):  
Fiona J. Sorrell ◽  
Lena Marie Kilian ◽  
Jonathan M. Elkins

Abstract The group A p21-activated kinases (PAKs) exist in an auto-inhibited form until activated by GTPase binding and auto-phosphorylation. In the auto-inhibited form, a regulatory domain binds to the kinase domain (KD) blocking the binding of substrates, and CDC42 or Rac binding to the regulatory domain relieves this auto-inhibition allowing auto-phosphorylation on the KD activation loop. We have determined the crystal structure of the PAK3 catalytic domain and by small angle X-ray scattering, the solution-phase structures of full-length inactive PAK1 and PAK3. The structures reveal a compact but elongated molecular shape that demonstrates that, together with multiple independent biophysical measurements and in contrast with previous assumptions, group A PAKs are monomeric both before and after activation, consistent with an activation mechanism of cis-auto-inhibition and initial cis-auto-phosphorylation, followed by transient dimerisation to allow trans-auto-phosphorylation for full activation, yielding a monomeric active PAK protein.


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