The roles of microtubule-associated proteins in brain morphogenesis: a review.

Publisher Summary This chapter reviews the structure and function of microtubule (MT)-associated proteins (MAP). The discovery of MAP with defined roles in MT-based motility, such as kinesin and cytoplasmic dynein, and important advances in the structural and morphological analyses of other MAP, including fibrous and nonfibrous MAP are discussed in the chapter. By using the tools of recombinant DNA technology, such as site-directed mutagenesis, transfection of truncated or otherwise mutated MAP genes into living cells, and synthetic peptides, the mechanisms of the various types of MAP-MT interactions and the influence of potential regulatory domains such as phosphorylation sites are determined. The proposed role of fibrous MAP as cross-linking elements mediating stable or transient interactions between MT and various other cell structures are summarized in the chapter. The only established function of MAP is the stabilization of MT. Increased stability of endogenous MT to depolymerizing agents is seen when purified tau proteins are microinjected into cells lacking tau. Another important cellular function of fibrous MAP, long proposed on grounds of in vitro experiments, is the promotion of MT assembly. The fibrous MAP also plays a role in morphogenesis by specifying the interaction partners of MT in different types and compartments of cells.

Molecular structure and function of microtubule-associated proteins.

Mitogen-activated protein kinase (MAPK), a serine/threonine-specific protein kinase which is generally activated by stimulation with various growth factors and phorbol esters, utilizes microtubule-associated protein (MAP) 2 as a good substrate in vitro. We have found that MAPK-catalyzed phosphorylation of MAP2 resulted in a significant loss in its ability to induce tubulin polymerization. The chymotryptic fragments, containing a microtubule-binding domain of MAP2, were phosphorylated by MAPK and the ability of the fragments to induce tubulin polymerization was also greatly decreased by the phosphorylation, suggesting that phosphorylation of the microtubule-binding domain is important for functional alteration of MAP2. In addition to MAP2, a 190-kDa heat-stable MAP (MAP4) found in various tissues and cells, was a good substrate for MAPK in vitro. Phosphorylation of MAP4 inactivated tubulin polymerization. We examined the effect of phosphorylation of MAP2 and MAP4 on the dynamics of microtubules nucleated by purified centrosomes in vitro. The data showed that MAPK-catalyzed phosphorylation of MAP2 and MAP4 reduced their ability to increase the apparent elongation rate and the number of microtubules nucleated by the centrosome. Thus, MAPK is capable of phosphorylating MAPs and negatively regulating their microtubule-stabilizing function.

Mitogen-activated-protein-kinase-catalyzed phosphorylation of microtubule-associated proteins, microtubule-associated protein 2 and microtubule-associated protein 4, induces an alteration in their function.

Molecular cloning of a ubiquitously distributed microtubule-associated protein with Mr 190,000.

Cet article resume les methodes d'isolement, les proprietes biochimiques et fonctionnelles des proteines associees aux microtubules, qui sont un des trois principaux elements filamenteux du cytosquelette. Ils sont formes par l'autoassociation de leur proteine majeure, la tubuline. De nombreuses proteines, souvent associees, interagissent avec les microtubules cellulaires

/pdf/high-mr-microtubule-associated-proteins-properties-and-2ym5r80e58.pdf

High-Mr microtubule-associated proteins: properties and functions.

We investigated the biochemical characteristics of microtubule-associated proteins (MAPs) of both the adrenal medulla and the cortex. The major constituents of the adrenal MAPs isolated by the taxol-dependent procedure [Vallee, R. B. (1982) J. Cell. Biol. 92, 435-442] were several polypeptides in the high-molecular-mass region (high-Mr MAPs) and a 190000-Mr polypeptide (190-kDa MAP). In the cortex MAP fraction, the most prominent component was 190-kDa MAP, while the medulla MAP fraction was rich in high-Mr MAPs. Twice-cycled microtubule proteins prepared without taxol from the same sources also contained high-Mr MAPs and 190-kDa MAP. High-Mr MAPs contained protein species identical to MAP1 and MAP2 of mammalian brain as judged from electrophoretic mobility, heat-stability and immunoreactivity. 190-kDa MAP was classified as MAP subspecies distinct from high-Mr MAPs by several criteria. The MAP fractions had the ability to polymerize purified tubulin into microtubules, and the major MAP species (high-Mr MAPs and 190-kDa MAP) were found to cosediment with reconstituted microtubules. Tau factor, one of the major MAPs in the mammalian brain, appeared to be a minor species in the adrenal gland.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1986.tb09543.x

Characterization of microtubule-associated proteins isolated from bovine adrenal gland

Insulin-like growth factor-I (IGF-I) stimulated the phosphorylation of cytoskeletal 350-kDa and 300-kDa proteins which were immunoprecipitated with antibodies against brain high molecular weight microtubule-associated proteins in quiescent rat 3Y1 cells. The data on the effec-tive concentrations of IGF-I and 125I-labeled IGF-I binding indicated that type I IGF receptors mediate this IGF-I effect. Platelet-derived growth factor (PDGF) as well as phorbol ester (TPA) also stimulated the phosphorylation of these proteins. These proteins, whether immunoprecipitated from cells stimulated by insulin, IGF-I, TPA, PDGF, or epidermal growth factor, produced very similar phosphopeptide mapping patterns irrespective of the stimulant. The results suggest the possibility that these growth factors and phorbol esters may activate a common protein kinase which is responsible for the phosphorylation of the 350-kDa and 300-kDa proteins in cells.

Stimulation of the phosphorylation of cytoskeletal 350-kDa and 300-kDa proteins by insulin-like growth factor-I, platelet-derived growth factor and phorbol ester in rat 3Y1 cells.

New categorization of human vascular endothelial cells by pro- vs anti-proliferative phenotypes

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Chikako Sato

Author Tools

Chat about Author

Papers

Characterization of microtubule-associated proteins isolated from bovine adrenal gland

Stimulation of the phosphorylation of cytoskeletal 350-kDa and 300-kDa proteins by insulin-like growth factor-I, platelet-derived growth factor and phorbol ester in rat 3Y1 cells.

New categorization of human vascular endothelial cells by pro- vs anti-proliferative phenotypes