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Ito H, Morishita R, Nagata KI. Simple Method for the Preparation of Postsynaptic Density Fraction from Mouse Brain. Methods Mol Biol 2024; 2794:71-78. [PMID: 38630221 DOI: 10.1007/978-1-0716-3810-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Postsynaptic density (PSD) is a morphologically and functionally specialized postsynaptic membrane structure of excitatory synapses. It contains hundreds of proteins such as neurotransmitter receptors, adhesion molecules, cytoskeletal proteins, and signaling enzymes. The study of the molecular architecture of the PSD is one of the most intriguing issues in neuroscience research. The isolation of the PSD from the brain of an animal is necessary for subsequent biochemical and morphological analyses. Many laboratories have developed methods to isolate PSD from the animal brain. In this chapter, we present a simple method to isolate PSD from the mouse brain using sucrose density gradient-based purification of synaptosomes followed by detergent extraction.
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Affiliation(s)
- Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Aichi, Japan.
| | - Rika Morishita
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Aichi, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Aichi, Japan
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Suzuki T, Terada N, Higashiyama S, Kametani K, Shirai Y, Honda M, Kai T, Li W, Tabuchi K. Non-microtubule tubulin-based backbone and subordinate components of postsynaptic density lattices. Life Sci Alliance 2021; 4:4/7/e202000945. [PMID: 34006534 PMCID: PMC8326785 DOI: 10.26508/lsa.202000945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/28/2022] Open
Abstract
This study proposes a postsynaptic density (PSD) lattice model comprising a non-microtubule tubulin-based backbone structure and its associated proteins, including various PSD scaffold/adaptor proteins and other PSD proteins. A purification protocol was developed to identify and analyze the component proteins of a postsynaptic density (PSD) lattice, a core structure of the PSD of excitatory synapses in the central nervous system. “Enriched”- and “lean”-type PSD lattices were purified by synaptic plasma membrane treatment to identify the protein components by comprehensive shotgun mass spectrometry and group them into minimum essential cytoskeleton (MEC) and non-MEC components. Tubulin was found to be a major component of the MEC, with non-microtubule tubulin widely distributed on the purified PSD lattice. The presence of tubulin in and around PSDs was verified by post-embedding immunogold labeling EM of cerebral cortex. Non-MEC proteins included various typical scaffold/adaptor PSD proteins and other class PSD proteins. Thus, this study provides a new PSD lattice model consisting of non-microtubule tubulin-based backbone and various non-MEC proteins. Our findings suggest that tubulin is a key component constructing the backbone and that the associated components are essential for the versatile functions of the PSD.
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Affiliation(s)
- Tatsuo Suzuki
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Nobuo Terada
- Health Science Division, Department of Medical Sciences, Graduate School of Medicine, Science and Technology, Shinshu University, Matsumoto, Nagano, Japan
| | - Shigeki Higashiyama
- Department of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, To-on, Ehime, Japan
| | - Kiyokazu Kametani
- Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Mamoru Honda
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Tsutomu Kai
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Weidong Li
- Bio-X Institutes, Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China.,Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan.,Department of Biological Sciences for Intractable Neurological Diseases, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
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Wolff J. Plasma membrane tubulin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1415-33. [PMID: 19328773 DOI: 10.1016/j.bbamem.2009.03.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 03/13/2009] [Accepted: 03/19/2009] [Indexed: 01/17/2023]
Abstract
The association of tubulin with the plasma membrane comprises multiple levels of penetration into the bilayer: from integral membrane protein, to attachment via palmitoylation, to surface binding, and to microtubules attached by linker proteins to proteins in the membrane. Here we discuss the soundness and weaknesses of the chemical and biochemical evidence marshaled to support these associations, as well as the mechanisms by which tubulin or microtubules may regulate functions at the plasma membrane.
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Affiliation(s)
- J Wolff
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Trinidad JC, Thalhammer A, Specht CG, Schoepfer R, Burlingame AL. Phosphorylation state of postsynaptic density proteins. J Neurochem 2005; 92:1306-16. [PMID: 15748150 DOI: 10.1111/j.1471-4159.2004.02943.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The postsynaptic density (PSD) is an electron-dense structure located at the synaptic contacts between neurons. Its considerable complexity includes cytoskeletal and scaffold proteins, receptors, ion channels and signaling molecules, in line with the role of PSDs in signal transduction and processing. The phosphorylation state of components of the PSD is central to synaptic transmission and is known to play a role in synaptic plasticity, learning and memory. The presence of a range of kinases and phosphatases in the PSD defines potential key players in this context. However, the substrates that these enzymes target have not been fully identified to date. We analyzed the protein composition of purified PSD samples from adult mouse brains by strong cation exchange chromatography fractionation of a tryptic digest followed by nano-reverse phase liquid chromatography coupled with electrospray ionization-quadrupole time of flight tandem mass spectrometry. This led to the identification of 244 proteins. To gain an insight into the phosphoproteome of the PSD we then purified phosphorylated tryptic peptides by immobilized metal ion affinity chromatography. This approach for the specific enrichment of phosphopeptides resulted in the identification of 42 phosphoproteins in the PSD preparation, 39 of which are known PSD components. Here we present a total of 83 in vivo phosphorylation sites.
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Affiliation(s)
- J C Trinidad
- Mass Spectrometry Facility, Department of Pharmaceutical Chemistry, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
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Suzuki T, Tanaka R. Characterization of Ca2+/calmodulin-dependent protein kinase associated with rat cerebral synaptic junction: substrate specificity and effect of autophosphorylation. J Neurochem 1986; 47:642-51. [PMID: 3734797 DOI: 10.1111/j.1471-4159.1986.tb04548.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The Ca2+/calmodulin (CaM)-dependent protein kinase associated with rat cerebral synaptic junction (SJ) was characterized, using the SJ fraction as the enzyme preparation, to clarify the functional significance of the enzyme in situ. The protein kinase was greatly activated in the presence of micromolar concentrations of both Ca2+ and calmodulin (EC50 for Ca2+, 1.0 microM; that for CaM, 100 nM). The Km for ATP was 150 microM. SJ proteins were phosphorylated without a lag time, and the phosphorylation reached its maximum within 2-10 min at 25 degrees C. The endogenous substrates consisted of four major (160K, 120K, 60K, and 51K Mr) and 10 minor proteins. Compared with the endogenous substrate phosphorylation, the phosphorylation of exogenously added proteins (myosin light chains from chicken muscle, casein, arginine-rich histone, microtubule-associated protein-2, tau-protein, and tubulin) was weak, although they are expected to be good substrates for the soluble form of the Ca2+/CaM-dependent protein kinase. Autophosphorylation of the enzyme in SJ inhibited its activity and did not alter the subcellular distribution of the enzyme.
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Yang ZW, Babitch JA. Detection and characterization of some new basic proteins in chicken postsynaptic densities. J Neurochem 1986; 47:282-90. [PMID: 3711904 DOI: 10.1111/j.1471-4159.1986.tb02860.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chicken brain postsynaptic density (PSD) polypeptides, obtained by treating synaptosomes with 0.5% Triton X-100 and then further purified on a sucrose gradient, are demonstrated to contain four basic proteins of 76K (pI greater than 9.2), 58K (pI 8.1-8.8, heterogeneous), 40K (pI 9.0), and 24K (pI 8.9). Nonequilibrium pH gradient-sodium dodecyl sulfate two-dimensional gels further reveal six more basic proteins with pI values higher than 9.2: 76K, 52K, 47K, 45K, 36K, and 34K. These basic proteins are a major part of the total chicken PSD polypeptides appearing on the gels. Some of these basic proteins (58K, 52K, 47K, 36K, 24K, and two at 76K) are distinguishable from those of brain mitochondria, the major contaminant. The 40K and 34K proteins may be common mitochondrial polypeptides. The 45K protein is probably a mitochondrial contaminant. A number of proteins including 76K (synapsin I-like protein) and 58K, along with some other minor ones, can be phosphorylated by endogenous protein kinase(s) in the presence of Ca2+, Mg2+, and [gamma-32P]ATP. No PSD basic proteins bind Ca2+.
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