[ { "id": "authors:s5g2v-v6876", "collection": "authors", "collection_id": "s5g2v-v6876", "cite_using_url": "https://authors.library.caltech.edu/records/s5g2v-v6876", "type": "article", "title": "FETCH enables fluorescent labeling of membrane proteins in vivo with spatiotemporal control in Drosophila", "author": [ { "family_name": "Rostam", "given_name": "Kevin D.", "orcid": "0009-0002-2222-4104", "clpid": "Rostam-Kevin-D" }, { "family_name": "Morano", "given_name": "Nicholas C.", "orcid": "0000-0002-8129-4033" }, { "family_name": "Menon", "given_name": "Kaushiki P.", "orcid": "0000-0003-1039-4704", "clpid": "Menon-Kaushiki-P" }, { "family_name": "Lopez", "given_name": "Davys H." }, { "family_name": "Shapiro", "given_name": "Lawrence" }, { "family_name": "Zinn", "given_name": "Kai George", "orcid": "0000-0002-6706-5605", "clpid": "Zinn-K" }, { "family_name": "Feng", "given_name": "Siqian", "orcid": "0000-0003-0650-9134" }, { "family_name": "Mann", "given_name": "Richard S.", "orcid": "0000-0002-4749-2765" } ], "abstract": "Fluorescent labeling approaches are crucial for elucidating protein function and dynamics. While robust methods to monitor gene transcription are widespread, the visualization of proteins in vivo is more elusive. To meet this challenge, we developed Fluorescent Endogenous Tagging with a Covalent Hook (FETCH) to label cell surface proteins (CSPs) in vivo through a stable covalent bond mediated by the DogTag-DogCatcher peptide partner system. FETCH leverages a spontaneous covalent isopeptide bond that forms between the 23-amino acid DogTag and the 15-kDa DogCatcher. Unlike most tags that work best at protein termini, DogTag functions well in protein loops, expanding the range of sites that can be targeted in proteins. In FETCH, DogTag is introduced into extracellular loops of CSPs through genome engineering, enabling covalent bond formation with a genetically encoded DogCatcher-GFP fusion protein that can be secreted from a variety of cell types in intact animals. To identify optimal DogTag insertions into CSPs, we describe a flow cytometry\u2013based platform for rapidly screening candidates in vitro. We demonstrate the ability to tag and visualize three members of the immunoglobulin superfamily (IgSF) in vivo: the transmembrane protein mCD8 and two GPI-anchored proteins belonging to the DIP-Dpr interactome that interact biophysically to facilitate neuronal target recognition at\n Drosophila\n neuromuscular and brain synapses. FETCH enables precise temporal and spatial control to visualize tagged proteins in vivo, features that are adaptable to a multitude of applications for modifying any cell surface protein.", "doi": "10.1073/pnas.2503166122", "pmcid": "PMC12557536", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences", "publication_date": "2025-10-21", "series_number": "42", "volume": "122", "issue": "42", "pages": "e2503166122" }, { "id": "authors:rp64r-j2h14", "collection": "authors", "collection_id": "rp64r-j2h14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210526-160617577", "type": "article", "title": "Neural mechanism of spatio-chromatic opponency in the Drosophila amacrine neurons", "author": [ { "family_name": "Li", "given_name": "Yan", "clpid": "Li-Yan" }, { "family_name": "Chen", "given_name": "Pei-Ju", "orcid": "0000-0002-7099-9169", "clpid": "Chen-Pei-Ju" }, { "family_name": "Lin", "given_name": "Tzu-Yang", "orcid": "0000-0002-1968-177X", "clpid": "Lin-Tzu-Yang" }, { "family_name": "Ting", "given_name": "Chun-Yuan", "orcid": "0000-0002-2302-4203", "clpid": "Ting-Chun-Yuan" }, { "family_name": "Muthuirulan", "given_name": "Pushpanathan", "orcid": "0000-0001-6240-3073", "clpid": "Muthuirulan-Pushpanathan" }, { "family_name": "Pursley", "given_name": "Randall", "orcid": "0000-0002-7933-3291", "clpid": "Pursley-Randall" }, { "family_name": "Ili\u0107", "given_name": "Marko", "clpid": "Ili\u0107-Marko" }, { "family_name": "Pirih", "given_name": "Primo\u017e", "clpid": "Pirih-Primo\u017e" }, { "family_name": "Drews", "given_name": "Michael S.", "clpid": "Drews-Michael-S" }, { "family_name": "Menon", "given_name": "Kaushiki P.", "orcid": "0000-0003-1039-4704", "clpid": "Menon-Kaushiki-P" }, { "family_name": "Zinn", "given_name": "Kai G.", "orcid": "0000-0002-6706-5605", "clpid": "Zinn-K" }, { "family_name": "Pohida", "given_name": "Thomas", "clpid": "Pohida-Thomas" }, { "family_name": "Borst", "given_name": "Alexander", "orcid": "0000-0001-5537-8973", "clpid": "Borst-Alexander" }, { "family_name": "Lee", "given_name": "Chi-Hon", "clpid": "Lee-Chi-Hon" } ], "abstract": "Visual animals detect spatial variations of light intensity and wavelength composition. Opponent coding is a common strategy for reducing information redundancy. Neurons equipped with both spatial and spectral opponency have been identified in vertebrates but not yet in insects. The Drosophila amacrine neuron Dm8 was recently reported to show color opponency. Here, we demonstrate Dm8 exhibits spatio-chromatic opponency. Antagonistic convergence of the direct input from the UV-sensing R7s and indirect input from the broadband receptors R1\u2013R6 through Tm3 and Mi1 is sufficient to confer Dm8's UV/Vis (ultraviolet/visible light) opponency. Using high resolution monochromatic stimuli, we show the pale and yellow subtypes of Dm8s, inheriting retinal mosaic characteristics, have distinct spectral tuning properties. Using 2D white-noise stimulus and reverse correlation analysis, we found that the UV receptive field (RF) of Dm8 has a center-inhibition/surround-excitation structure. In the absence of UV-sensing R7 inputs, the polarity of the RF is inverted owing to the excitatory input from the broadband photoreceptors R1\u2013R6. Using a new synGRASP method based on endogenous neurotransmitter receptors, we show that neighboring Dm8s form mutual inhibitory connections mediated by the glutamate-gated chloride channel GluCl\u03b1, which is essential for both Dm8's spatial opponency and animals' phototactic behavior. Our study shows spatio-chromatic opponency could arise in the early visual stage, suggesting a common information processing strategy in both invertebrates and vertebrates.", "doi": "10.1016/j.cub.2021.04.068", "issn": "0960-9822", "publisher": "Cell Press", "publication": "Current Biology", "publication_date": "2021-07-26", "series_number": "14", "volume": "31", "issue": "14", "pages": "3040-3052" }, { "id": "authors:9ckxj-e0r50", "collection": "authors", "collection_id": "9ckxj-e0r50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150625-105310954", "type": "article", "title": "The translational regulator Cup controls NMJ presynaptic terminal morphology", "author": [ { "family_name": "Menon", "given_name": "Kaushiki P.", "orcid": "0000-0003-1039-4704", "clpid": "Menon-Kaushiki-P" }, { "family_name": "Carrillo", "given_name": "Robert A.", "orcid": "0000-0002-2067-9861", "clpid": "Carrillo-Robert-A" }, { "family_name": "Zinn", "given_name": "Kai", "orcid": "0000-0002-6706-5605", "clpid": "Zinn-K" } ], "abstract": "During oogenesis and early embryonic development in Drosophila, translation of proteins from maternally deposited mRNAs is tightly controlled. We and others have previously shown that translational regulatory proteins that function during oogenesis also have essential roles in the nervous system. Here we examine the role of Cup in neuromuscular system development. Maternal Cup controls translation of localized mRNAs encoding the Oskar and Nanos proteins and binds to the general translation initiation factor eIF4E. In this paper, we show that zygotic Cup protein is localized to presynaptic terminals at larval neuromuscular junctions (NMJs). cup mutant NMJs have strong phenotypes characterized by the presence of small clustered boutons called satellite boutons. They also exhibit an increase in the frequency of spontaneous glutamate release events (mEPSPs). Reduction of eIF4E expression synergizes with partial loss of Cup expression to produce satellite bouton phenotypes. The presence of satellite boutons is often associated with increases in retrograde bone morphogenetic protein (BMP) signaling, and we show that synaptic BMP signaling is elevated in cup mutants. cup genetically interacts with four genes (EndoA, WASp, Dap160, and Synj) encoding proteins involved in endocytosis that are also neuronal modulators of the BMP pathway. Endophilin protein, encoded by the EndoA gene, is downregulated in a cup mutant. Our results are consistent with a model in which Cup and eIF4E work together to ensure efficient localization and translation of endocytosis proteins in motor neurons and control the strength of the retrograde BMP signal.", "doi": "10.1016/j.mcn.2015.06.010", "pmcid": "PMC4540612", "issn": "1044-7431", "publisher": "Elsevier", "publication": "Molecular and Cellular Neuroscience", "publication_date": "2015-07", "volume": "67", "pages": "126-136" } ]