scholarly journals A polybasic domain in aPKC mediates Par6-dependent control of membrane targeting and kinase activity

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Wei Dong ◽  
Juan Lu ◽  
Xuejing Zhang ◽  
Yan Wu ◽  
Kaela Lettieri ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Protein Interactions ◽  
Calcium Binding ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Cell Polarization ◽  
Physical Interaction ◽  
Protein Protein Interactions ◽  
Binding Domains ◽  
Electrostatic Binding

Mechanisms coupling the atypical PKC (aPKC) kinase activity to its subcellular localization are essential for cell polarization. Unlike other members of the PKC family, aPKC has no well-defined plasma membrane (PM) or calcium binding domains, leading to the assumption that its subcellular localization relies exclusively on protein–protein interactions. Here we show that in both Drosophila and mammalian cells, the pseudosubstrate region (PSr) of aPKC acts as a polybasic domain capable of targeting aPKC to the PM via electrostatic binding to PM PI4P and PI(4,5)P2. However, physical interaction between aPKC and Par-6 is required for the PM-targeting of aPKC, likely by allosterically exposing the PSr to bind PM. Binding of Par-6 also inhibits aPKC kinase activity, and such inhibition can be relieved through Par-6 interaction with apical polarity protein Crumbs. Our data suggest a potential mechanism in which allosteric regulation of polybasic PSr by Par-6 couples the control of both aPKC subcellular localization and spatial activation of its kinase activity.

scholarly journals A Polybasic Domain in aPKC Mediates Par6-Dependent Control of Membrane Targeting and Kinase Activity

2019 ◽  
Author(s):  
Wei Dong ◽  
Juan Lu ◽  
Xuejing Zhang ◽  
Yan Wu ◽  
Kaela Lettieri ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Subcellular Localization ◽  
Protein Interactions ◽  
Calcium Binding ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Allosteric Regulation ◽  
Cell Polarization ◽  
Physical Interaction ◽  
Binding Domains

SUMMARYMechanisms coupling the atypical PKC (aPKC) kinase activity to its subcellular localization are essential for cell polarization. Unlike other members of the PKC family, aPKC has no well-defined plasma membrane (PM) or calcium binding domains, leading to the assumption that its subcellular localization relies exclusively on protein-protein interactions. Here we show that in both Drosophila and mammalian cells the pseudosubstrate region (PSr) of aPKC acts as a polybasic domain capable of targeting aPKC to the PM via electrostatic binding to PM PI4P and PI(4,5)P2. However, physical interaction between aPKC and Par-6 is required for the PM-targeting of aPKC, likely by allosterically exposing the PSr to bind PM. Binding of Par-6 also inhibits aPKC kinase activity and such inhibition can be relieved through Par-6 interaction with apical polarity protein Crumbs. Our data suggest a potential mechanism in which allosteric regulation of polybasic PSr by Par-6 couples the control of both aPKC subcellular localization and spatial activation of its kinase activity.eTOC SummaryDong et al. discover that the pseudo-substrate region (PSr) in aPKC is a polybasic domain capable of electrostatically targeting aPKC to plasma membrane. Allosteric regulation of PSr by Par-6 couples the control of both aPKC subcellular localization and spatial activation of kinase activity.

An efficient transient assays system using Agrobacterium-mediated transformation of onion (Allium cepa) epidermal cells

2020 ◽  
Vol 80 (03) ◽  
Author(s):  
Yu-Miao Zhang ◽  
Jun Wang ◽  
Tao Wu
Keyword(s):  
Subcellular Localization ◽  
Protein Interaction ◽  
Protein Interactions ◽  
Epidermal Cells ◽  
Cyclin Dependent Kinase ◽  
Protein Subcellular Localization ◽  
Protein Protein Interactions ◽  
Efficient System ◽  
Protein Protein Interaction ◽  
Onion Epidermal Cells

In this study, the Agrobacterium infection medium, infection duration, detergent, and cell density were optimized. The sorghum-based infection medium (SbIM), 10-20 min infection time, addition of 0.01% Silwet L-77, and Agrobacterium optical density at 600 nm (OD600), improved the competence of onion epidermal cells to support Agrobacterium infection at >90% efficiency. Cyclin-dependent kinase D-2 (CDKD-2) and cytochrome c-type biogenesis protein (CYCH), protein-protein interactions were localized. The optimized procedure is a quick and efficient system for examining protein subcellular localization and protein-protein interaction.

IL-14 MAPPIT: a versatile METHOD to study protein-protein interactions in mammalian cells

2003 ◽  
Vol 16 (5) ◽  
pp. 577-577
Author(s):  
J. Tavernier ◽  
S. Eyckerman ◽  
I. Lemmens ◽  
S. Lievens ◽  
J. Vandekerckhove ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
Protein Protein Interactions

scholarly journals β-Catenin is a pH sensor with decreased stability at higher intracellular pH

2018 ◽  
Vol 217 (11) ◽  
pp. 3965-3976 ◽  
Author(s):  
Katharine A. White ◽  
Bree K. Grillo-Hill ◽  
Mario Esquivel ◽  
Jobelle Peralta ◽  
Vivian N. Bui ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Ph Sensor ◽  
Adherens Junction ◽  
Protein Protein Interactions ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Evolutionarily Conserved ◽  
Ph Dependent

β-Catenin functions as an adherens junction protein for cell–cell adhesion and as a signaling protein. β-catenin function is dependent on its stability, which is regulated by protein–protein interactions that stabilize β-catenin or target it for proteasome-mediated degradation. In this study, we show that β-catenin stability is regulated by intracellular pH (pHi) dynamics, with decreased stability at higher pHi in both mammalian cells and Drosophila melanogaster. β-Catenin degradation requires phosphorylation of N-terminal residues for recognition by the E3 ligase β-TrCP. While β-catenin phosphorylation was pH independent, higher pHi induced increased β-TrCP binding and decreased β-catenin stability. An evolutionarily conserved histidine in β-catenin (found in the β-TrCP DSGIHS destruction motif) is required for pH-dependent binding to β-TrCP. Expressing a cancer-associated H36R–β-catenin mutant in the Drosophila eye was sufficient to induce Wnt signaling and produced pronounced tumors not seen with other oncogenic β-catenin alleles. We identify pHi dynamics as a previously unrecognized regulator of β-catenin stability, functioning in coincidence with phosphorylation.

scholarly journals TULP1 and TUB Are Required for Specific Localization of PRCD to Photoreceptor Outer Segments

2020 ◽  
Vol 21 (22) ◽  
pp. 8677
Author(s):  
Lital Remez ◽  
Ben Cohen ◽  
Mariela J. Nevet ◽  
Leah Rizel ◽  
Tamar Ben-Yosef
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
Outer Segment ◽  
Protein Protein Interactions ◽  
Photoreceptor Outer Segment ◽  
Photoreceptor Outer Segments ◽  
Outer Segments ◽  
Yeast Two Hybrid System ◽  
Specific Localization ◽  
Recruitment System

Photoreceptor disc component (PRCD) is a small protein which is exclusively localized to photoreceptor outer segments, and is involved in the formation of photoreceptor outer segment discs. Mutations in PRCD are associated with retinal degeneration in humans, mice, and dogs. The purpose of this work was to identify PRCD-binding proteins in the retina. PRCD protein-protein interactions were identified when implementing the Ras recruitment system (RRS), a cytoplasmic-based yeast two-hybrid system, on a bovine retina cDNA library. An interaction between PRCD and tubby-like protein 1 (TULP1) was identified. Co-immunoprecipitation in transfected mammalian cells confirmed that PRCD interacts with TULP1, as well as with its homolog, TUB. These interactions were mediated by TULP1 and TUB highly conserved C-terminal tubby domain. PRCD localization was altered in the retinas of TULP1- and TUB-deficient mice. These results show that TULP1 and TUB, which are involved in the vesicular trafficking of several photoreceptor proteins from the inner segment to the outer segment, are also required for PRCD exclusive localization to photoreceptor outer segment discs.

Protein-Protein Interactions (PPIs) as an Alternative to Targeting the ATP Binding Site of Kinase

2016 ◽  
pp. 249-277
Author(s):  
Sailu Sarvagalla ◽  
Mohane Selvaraj Coumar
Keyword(s):  
Protein Interactions ◽  
In Silico ◽  
Rational Design ◽  
Kinase Activity ◽  
Hot Spot ◽  
Binding Pocket ◽  
Atp Binding ◽  
Protein Protein Interactions ◽  
Structure Based Drug Design ◽  
Atp Binding Site

Most of the developed kinase inhibitor drugs are ATP competitive and suffer from drawbacks such as off-target kinase activity, development of resistance due to mutation in the ATP binding pocket and unfavorable intellectual property situations. Besides the ATP binding pocket, protein kinases have binding sites that are involved in Protein-Protein Interactions (PPIs); these PPIs directly or indirectly regulate the protein kinase activity. Of recent, small molecule inhibitors of PPIs are emerging as an alternative to ATP competitive agents. Rational design of inhibitors for kinase PPIs could be carried out using molecular modeling techniques. In silico tools available for the prediction of hot spot residues and cavities at the PPI sites and the means to utilize this information for the identification of inhibitors are discussed. Moreover, in silico studies to target the Aurora B-INCENP PPI sites are discussed in context. Overall, this chapter provides detailed in silico strategies that are available to the researchers for carrying out structure-based drug design of PPI inhibitors.

scholarly journals Shaping the regulation of the p53 mRNA tumour suppressor: the co-evolution of genetic signatures

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Konstantinos Karakostis ◽  
Robin Fåhraeus
Keyword(s):  
Protein Interactions ◽  
Rna Structure ◽  
Mammalian Cells ◽  
Rna World ◽  
Genetic Diseases ◽  
Protein Protein Interactions ◽  
Activation Domain ◽  
Interacting Protein ◽  
Protein Motifs ◽  
Synonymous Mutations

Abstract Structured RNA regulatory motifs exist from the prebiotic stages of the RNA world to the more complex eukaryotic systems. In cases where a functional RNA structure is within the coding sequence a selective pressure drives a parallel co-evolution of the RNA structure and the encoded peptide domain. The p53-MDM2 axis, describing the interactions between the p53 tumor suppressor and the MDM2 E3 ubiquitin ligase, serves as particularly useful model revealing how secondary RNA structures have co-evolved along with corresponding interacting protein motifs, thus having an impact on protein – RNA and protein – protein interactions; and how such structures developed signal-dependent regulation in mammalian systems. The p53(BOX-I) RNA sequence binds the C-terminus of MDM2 and controls p53 synthesis while the encoded peptide domain binds MDM2 and controls p53 degradation. The BOX-I peptide domain is also located within p53 transcription activation domain. The folding of the p53 mRNA structure has evolved from temperature-regulated in pre-vertebrates to an ATM kinase signal-dependent pathway in mammalian cells. The protein – protein interaction evolved in vertebrates and became regulated by the same signaling pathway. At the same time the protein - RNA and protein - protein interactions evolved, the p53 trans-activation domain progressed to become integrated into a range of cellular pathways. We discuss how a single synonymous mutation in the BOX-1, the p53(L22 L), observed in a chronic lymphocyte leukaemia patient, prevents the activation of p53 following DNA damage. The concepts analysed and discussed in this review may serve as a conceptual mechanistic paradigm of the co-evolution and function of molecules having roles in cellular regulation, or the aetiology of genetic diseases and how synonymous mutations can affect the encoded protein.

scholarly journals aPKC: the Kinase that Phosphorylates Cell Polarity

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 903 ◽  
Author(s):  
Yang Hong
Keyword(s):  
Subcellular Localization ◽  
Cell Polarity ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Cell Polarization ◽  
Kinase C ◽  
Dividing Cells ◽  
Cell Embryo ◽  
Powerful Mechanism ◽  
Anterior Posterior

Establishing and maintaining cell polarity are dynamic processes that necessitate complicated but highly regulated protein interactions. Phosphorylation is a powerful mechanism for cells to control the function and subcellular localization of a target protein, and multiple kinases have played critical roles in cell polarity. Among them, atypical protein kinase C (aPKC) is likely the most studied kinase in cell polarity and has the largest number of downstream substrates characterized so far. More than half of the polarity proteins that are essential for regulating cell polarity have been identified as aPKC substrates. This review covers mainly studies of aPKC in regulating anterior-posterior polarity in the worm one-cell embryo and apical-basal polarity in epithelial cells and asymmetrically dividing cells (for example, Drosophila neuroblasts). We will go through aPKC target proteins in cell polarity and discuss various mechanisms by which aPKC phosphorylation controls their subcellular localizations and biological functions. We will also review the recent progress in determining the detailed molecular mechanisms in spatial and temporal control of aPKC subcellular localization and kinase activity during cell polarization.

scholarly journals Mass spectrometry-based methods for analysing the mitochondrial interactome in mammalian cells

2019 ◽  
Vol 167 (3) ◽  
pp. 225-231 ◽  
Author(s):  
Takumi Koshiba ◽  
Hidetaka Kosako
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Protein Complexes ◽  
Living Cells ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Protein Protein Interaction ◽  
Membrane Protein Complexes ◽  
Protein Protein Interaction Networks

Abstract Protein–protein interactions are essential biologic processes that occur at inter- and intracellular levels. To gain insight into the various complex cellular functions of these interactions, it is necessary to assess them under physiologic conditions. Recent advances in various proteomic technologies allow to investigate protein–protein interaction networks in living cells. The combination of proximity-dependent labelling and chemical cross-linking will greatly enhance our understanding of multi-protein complexes that are difficult to prepare, such as organelle-bound membrane proteins. In this review, we describe our current understanding of mass spectrometry-based proteomics mapping methods for elucidating organelle-bound membrane protein complexes in living cells, with a focus on protein–protein interactions in mitochondrial subcellular compartments.

Sign in / Sign up

Export Citation Format

Share Document