Protocols in Current Issue
    Visible Immunoprecipitation (VIP) Assay: a Simple and Versatile Method for Visual Detection of Protein-protein Interactions
    Authors:  Yohei Katoh, Kentaro Nakamura and Kazuhisa Nakayama, date: 01/05/2018, view: 272, Q&A: 0
    [Abstract] The visible immunoprecipitation (VIP) assay is a convenient alternative to conventional co-immunoprecipitation (Katoh et al., 2015). By processing lysates from cells co-expressing GFP-fusion and RFP-fusion proteins for immunoprecipitation with GST-tagged anti-GFP Nanobody and glutathione-Sepharose beads, protein-protein interactions can ...
    A General Method for Intracellular Protein Delivery through ‘E-tag’ Protein Engineering and Arginine Functionalized Gold Nanoparticles
    Authors:  Rubul Mout and Vincent M. Rotello, date: 12/20/2017, view: 502, Q&A: 0
    [Abstract] In this protocol, we describe a method for direct cytosolic protein delivery that avoids endosomal entrapment of the delivered proteins. We achieved this by tagging the desired protein with an oligo glutamic acid tag (E-tag), and subsequently using carrier gold nanoparticles to deliver these E-tagged proteins. When E-tagged proteins and ...
    Measuring the Endocytic Recycling of Amyloid Precursor Protein (APP) in Neuro2a Cells
    Authors:  Florent Ubelmann, Tatiana Burrinha and Claudia Guimas Almeida, date: 12/05/2017, view: 415, Q&A: 0
    [Abstract] The established primary trigger of Alzheimer’s disease’s is β-amyloid (Aβ) (Mucke and Selkoe, 2012). Amyloid precursor protein (APP) endocytosis is required for Aβ generation at early endosomes (Rajendran and Annaert, 2012). APP retention at endosomes also depends on its recycling back to the plasma membrane (Koo et al., 1996; Ubelmann et ...
    Bioluminescence Resonance Energy Transfer (BRET) Assay for Determination of Molecular Interactions in Living Cells
    [Abstract] The bioluminescence resonance energy transfer (BRET) assay can be used as an indicator of molecular approximation and/or interaction. A significant resonance energy transfer signal is generated when the acceptor, having the appropriate spectral overlap with the donor emission, is approximated with the donor. In the example provided, proteins ...
    Detection of Membrane Protein Interactions by Cell-based Tango Assays
    [Abstract] The Tango assay is a protein-protein interaction assay, in which a transcription factor (rTA) is fused to a membrane-bound protein via a linker that contains a cleavage site for TEV protease, whereas a soluble interaction partner is fused to TEV protease (Barnea et al., 2008). Association between the two interaction partners leads to an ...
    Streptavidin Bead Pulldown Assay to Determine Protein Homooligomerization
    [Abstract] Pulldown assay is a conventional method to determine protein-protein interactions in vitro. Expressing a protein of interest with two different tags allows testing whether both versions can be captured via one of the two tags as homooligomeric complex. This protocol is based on streptavidin bead capture of a biotinylated protein and ...
    γ-Secretase Epsilon-cleavage Assay
    [Abstract] γ-Secretase epsilon-cleavage assay is derived from the cell-based Tango assay (Kang et al., 2015), and is a fast and sensitive method to determine the initial cleavage of C99 by γ-secretase. In this protocol, we use HTL cells, which are HEK293 cells with a stably integrated luciferase reporter under the control of the bacterial tetO ...
    An Affinity-directed Protein Missile (AdPROM) System for Targeted Destruction of Endogenous Proteins
    Authors:  Thomas J Macartney, Gopal P Sapkota and Luke J Fulcher, date: 11/20/2017, view: 600, Q&A: 0
    [Abstract] We recently reported an Affinity-directed PROtein Missile (AdPROM) system for the targeted proteolysis of endogenous proteins of interest (POI) (Fulcher et al., 2016 and 2017). AdPROM consists of the Von Hippel Lindau (VHL) protein, a Cullin 2 E3 ligase substrate receptor (Bosu and Kipreos, 2008), conjugated to a high affinity polypeptide ...
    In vitro NLK Kinase Assay
    Authors:  Sungho Moon, Jiyoung Kim and Eek‐hoon Jho, date: 11/05/2017, view: 564, Q&A: 0
    [Abstract] This protocol provides step by step instructions to perform an in vitro kinase assay for nemo-like kinase. In addition, this protocol also describes an efficient method using mild lysis buffer for expression and purification of Glutathione S-transferase (GST) fusion proteins.
    Monitoring the Targeting of Cathepsin D to the Lysosome by Metabolic Labeling and Pulse-chase Analysis
    Authors:  Lucas A. Tavares and Luis L. P. daSilva, date: 11/05/2017, view: 639, Q&A: 0
    [Abstract] Mannose 6-phosphate receptors function can be studied in living cells by investigating alterations in processing and secretion of their ligand Cathepsin D. The assay described here is well established in the literature and comprises the metabolic labeling of newly synthesized proteins with [35S] methionine-cysteine in HeLa cells to ...