1
|
Helmke S, Lohse K, Mikule K, Wood MR, Pfenninger KH. SRC binding to the cytoskeleton, triggered by growth cone attachment to laminin, is protein tyrosine phosphatase-dependent. J Cell Sci 1998; 111 ( Pt 16):2465-75. [PMID: 9683640 DOI: 10.1242/jcs.111.16.2465] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The interaction of the non-receptor tyrosine kinase, Src, with the cytoskeleton of adhesion sites was studied in nerve growth cones isolated from fetal rat brain. Of particular interest was the role of protein tyrosine phosphatases in the regulation of Src-cytoskeleton binding. Growth cones were found to contain a high level of protein tryrosine phosphatase activity, most of it membrane-associated and forming large, multimeric and wheat germ agglutinin-binding complexes. The receptor tyrosine phosphatase PTPalpha seems to be the most prevalent species among the membrane-associated enzymes. As seen by immunofluorescence, PTPalpha is present throughout the plasmalemma of the growth cone including filopodia, and it forms a punctate pattern consistent with that of integrin beta1. For adhesion site analysis, isolated growth cones were either plated onto the neurite growth substratum, laminin, or kept in suspension. Plating growth cones on laminin triggered an 8-fold increase in Src binding to the adherent cytoskeleton. This effect was blocked completely with the protein tyrosine phosphatase inhibitor, vanadate. Growth cone plating also increased the association with adhesion sites of tyrosine phosphatase activity (14-fold) and of PTPalpha immunoreactivity (6-fold). Vanadate blocked the enzyme activity but not the recruitment of PTPalpha to the adhesion sites. In conjunction with our previous results on growth cones, these data suggest that integrin binding to laminin triggers the recruitment of PTPalpha (and perhaps other protein tyrosine phosphatases) to adhesion sites, resulting in de-phosphorylation of Src's tyr 527. As a result Src unfolds, becomes kinase-active, and its SH2 domain can bind to an adhesion site protein. This implies a critical role for protein tyrosine phosphatase activity in the earliest phases of adhesion site assembly.
Collapse
Affiliation(s)
- S Helmke
- Department of Cellular and Structural Biology, University of Colorado School of Medicine, and University of Colorado Cancer Center, Denver, Colorado 80262, USA
| | | | | | | | | |
Collapse
|
2
|
Riggott MJ, Matthew WD. Neurite outgrowth is enhanced by anti-idiotypic monoclonal antibodies to the ganglioside GM1. Exp Neurol 1997; 145:278-87. [PMID: 9184130 DOI: 10.1006/exnr.1997.6459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Exogenously added gangliosides enhance sprouting, neurite outgrowth, and other neuronal activities; this effect may be initiated when a ganglioside binds to a membrane protein or when a ganglioside intercalates into the plasma membrane. To test whether binding to membrane proteins is sufficient for ganglioside-mediated activity, anti-idiotypic antibodies were generated that mimic the functional binding sites of the ganglioside GM1 as described by M. J. Riggott and W. D. Matthew (1996, Glycobiology, 6, 581-589). These anti-idiotypic antibodies are proteinaceous probes that model the biochemical and biological effects of gangliosides. Those anti-idiotypic ganglioside (AIG) monoclonal antibodies (mAb's) were selected based on their ability to bind a known GM1 binding protein, the beta-subunit of cholera toxin. These studies described neuronal cell surface proteins that were identified by immunocytochemistry and Western blotting using these AIG mAb's. Here we show that AIG mAb's mimic the functional properties of GM1 in that they facilitate neurite outgrowth from central and peripheral nervous system neurons in in vitro bioassays. In addition, AIG mAb binding modulates second messenger activity, suggesting that membrane protein binding alone is sufficient to invoke intracellular activation. The similarity in the pattern of protein tyrosine phosphorylation evoked by GM1 and the anti-idiotypic ganglioside antibodies suggests that the AIG mAb's modulate neurite outgrowth in a manner similar to that of GM1. Because antibodies cannot intercalate into the plasma membrane, these results suggest that the ganglioside GM1 can mediate neuronal cellular activity by binding to cell surface proteins.
Collapse
Affiliation(s)
- M J Riggott
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
| | | |
Collapse
|
3
|
Leventhal PS, Feldman EL. Tyrosine phosphorylation and enhanced expression of paxillin during neuronal differentiation in vitro. J Biol Chem 1996; 271:5957-60. [PMID: 8626373 DOI: 10.1074/jbc.271.11.5957] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Tyrosine phosphorylation has been implicated as a means by which neurite outgrowth is regulated. Because paxillin is a tyrosine-phosphorylated protein that may play a role in regulating cell morphology, we examined its expression in neuronal cells and how its tyrosine phosphorylation is related to neurite outgrowth. Paxillin was identified in several neuronal cell lines with an increased level upon differentiation. In SH-SY5Y cells, paxillin was localized along with actin filaments where processes extended from the cell body and in neuritic growth cones. Furthermore, paxillin was tyrosine-phosphorylated in SH-SY5Y cells upon adhesion to laminin. Paxillin tyrosine phosphorylation paralleled that of focal adhesion kinase and occurred as cell spreading, and neurite formation was initiated. Colchicine blocked neurite outgrowth but had no effect on cell spreading or on paxillin or focal adhesion kinase tyrosine phosphorylation. In contrast, cytochalasin D eliminated neurite outgrowth, cell spreading, and the tyrosine phosphorylation of paxillin and focal adhesion kinase. These results show that paxillin is tyrosine-phosphorylated upon integrin ligand binding in neuronal cells. Our findings suggest that paxillin tyrosine phosphorylation is linked to a remodeling of the actin cytoskeleton that leads to cell spreading and neurite formation and thus a differentiated neuronal phenotype.
Collapse
Affiliation(s)
- P S Leventhal
- Department of Neurology, University of Michigan, Ann Arbor 48109-0588, USA
| | | |
Collapse
|
4
|
Burgaya F, Menegon A, Menegoz M, Valtorta F, Girault JA. Focal adhesion kinase in rat central nervous system. Eur J Neurosci 1995; 7:1810-21. [PMID: 7582133 DOI: 10.1111/j.1460-9568.1995.tb00700.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Focal adhesion kinase (pp125FAK, FAK) is a 125 kDa non-receptor tyrosine kinase enriched in focal adhesions of various cell types, where it is thought to transduce signals triggered by contact with the extracellular matrix. We have studied the expression and localization of FAK in rat CNS. Immunoblotting, immunohistochemistry and in situ hybridization revealed the presence of FAK in all regions of the adult brain and demonstrated its enrichment in specific neuronal populations of the cerebral and cerebellar cortex, as well as in the hippocampus. During development, FAK protein levels were highest around birth in cerebral cortex and caudate putamen and decreased in the adult. In situ hybridization revealed enrichment of FAK mRNA in the ventricular germinative and external layers during the last period of embryonic growth. In primary cultures FAK immunoreactivity was localized in focal adhesions in astrocytes, whereas in developing neurons the highest levels were found in growth cones and perikarya. In the growth cone, FAK immunoreactivity colocalized with actin filaments. In mature neurons FAK appeared to be distributed in the whole cytoplasm, with no enrichment in any cellular compartment. Our results demonstrate the presence of high levels of FAK in rat CNS, maximal during development but persistent in the adult. Its enrichment in growth cones suggests that it may play a role in neurite outgrowth, as well as in plasticity in the adult.
Collapse
Affiliation(s)
- F Burgaya
- INSERM U114, Collège de France, Paris, France
| | | | | | | | | |
Collapse
|
5
|
Jian X, Hidaka H, Schmidt JT. Kinase requirement for retinal growth cone motility. JOURNAL OF NEUROBIOLOGY 1994; 25:1310-28. [PMID: 7815061 DOI: 10.1002/neu.480251011] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Since cytoplasmic Ca2+ levels are reported to regulate neurite elongation, we tested whether calcium-activated kinases might be necessary for growth cone motility and neurite elongation in explant cultures of goldfish retina. Kinase inhibitors and activators were locally applied by micropipette to retinal growth cones and the responses were observed via phase-contrast videomicroscopy. In some cases, growth rates were also quantified over several hours after general application in the medium. The selective inhibitors of protein kinase C, calphostin C (0.1-1 microM) and chelerythrin (up to 50 microM), caused no obvious changes in growth cones or neurite elongation, and activators of PKC (phorbols, arachidonic acid, and diacylglycerol) also were generally without effects, although phorbols slowed the growth rate. Inhibitors of protein kinase A and tyrosine kinases also produced no obvious effects. The calmodulin antagonists, calmidazolium (0.1 microM), trifluoperazine (100 microM), and CGS9343B (50 microM), however, caused a reversible growth cone arrest with loss of filopodia and lamellipodia. The growth cone became a club-shaped swelling which sometimes moved a short distance back the shaft, leaving evacuated filaments at points of strong filopodial attachments. A similar reversible growth cone arrest occurred with the general kinase inhibitors: H7 at 200 but not at 100 microM, and staurosporine at 100 but not 10 nM, suggesting possible involvement of a calmodulin-dependent kinase (camK) rather than PKC. The selective inhibitor of camKII, KN-62 (tested up to 50 microM), produced no effects, but the specific myosin light-chain kinase (MLCK) inhibitors ML-7 (3-5 microM) and ML-9 (5-10 microM) reversibly reproduced the effect, suggesting that MLCK rather than camKII is necessary for growth cone motility. The MLCK inhibitors' effects both on growth cone morphology and on F-actin filaments (rhodamine-phalloidin staining) were similar to those caused by cytochalasin D (5 microM), and are discussed in light of findings that inhibiting MLCK disrupts actin filaments in astrocytes and fibroblasts.
Collapse
Affiliation(s)
- X Jian
- Department of Biological Sciences, State University of New York at Albany 12222
| | | | | |
Collapse
|
6
|
Siciliano JC, Gelman M, Girault JA. Depolarization and neurotransmitters increase neuronal protein tyrosine phosphorylation. J Neurochem 1994; 62:950-9. [PMID: 7509378 DOI: 10.1046/j.1471-4159.1994.62030950.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In rat hippocampal slices and in neurons in primary culture, K(+)-induced depolarization increased markedly and rapidly tyrosine phosphorylation of a 110-kDa protein (pp110) and, to a lesser degree, of a 120-kDa protein (pp120), in a calcium-dependent fashion. Glutamate, 1-aminocyclopentane-trans-1,3-dicarboxylic acid (an agonist of metabotropic glutamate receptors), and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (an agonist of ionotropic glutamate receptors) stimulated also tyrosine phosphorylation of pp110 and pp120. These effects were not observed in astrocytes in primary culture. In hippocampal slices tyrosine phosphorylation of pp110 and pp120 was stimulated by Ca(2+)-ionophores and by phorbol esters and antagonized by a chelator of intracellular Ca2+ and by drugs that inhibit protein kinase C. Stimulation of muscarinic and alpha 1-adrenergic receptors increased also tyrosine phosphorylation of pp110 and pp120. These results demonstrate that membrane depolarization and stimulation of neurotransmitter receptors activate a tyrosine phosphorylation pathway in neurons. This pathway involves an increase in intracellular Ca2+ concentrations and the activation of protein kinase C. It may provide a biochemical basis for some neurotrophic effects of electrical activity and neurotransmitters and may contribute to the role of tyrosine phosphorylation in long-term potentiation.
Collapse
Affiliation(s)
- J C Siciliano
- INSERM U. 114, Chaire de Neuropharmacologie, Collège de France, Paris, France
| | | | | |
Collapse
|
7
|
Faúndez V, Krauss R, Holuigue L, Garrido J, González A. Epidermal growth factor receptor in synaptic fractions of the rat central nervous system. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)88710-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
8
|
Woodrow S, Bissoon N, Gurd JW. Depolarization-dependent tyrosine phosphorylation in rat brain synaptosomes. J Neurochem 1992; 59:857-62. [PMID: 1379632 DOI: 10.1111/j.1471-4159.1992.tb08323.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Synaptosomes from rat forebrain were analyzed for the presence of phosphotyrosine-containing proteins by immunoblotting with antiphosphotyrosine antibodies. Using this technique, 10-11 phosphotyrosine-containing proteins were detected. Depolarization of synaptosomes by transfer to a high (41 mM) K+ medium resulted in increases in the phosphotyrosine content of several synaptosomal proteins, the most pronounced increase being associated with a membrane protein of M(r) 117,000 (ptp117). Additional proteins exhibiting depolarization-dependent increases in phosphotyrosine content had molecular weights of 39,000, 104,000, 135,000, and 160,000. The depolarization-dependent increase in the phosphotyrosine content of ptp117 was apparent within 30 s of the onset of depolarization, reached a maximum between 3 and 5 min, and then decreased to near control values by 30 min. The increase in tyrosine phosphorylation of ptp117 was dependent on the concentration of K+ in the depolarizing medium and was maximal with [K+] in excess of 50 mM. It was also calcium dependent and did not occur in the absence of extracellular calcium. The addition of veratridine to the incubation medium also resulted in an increase in the tyrosine phosphorylation of ptp117. The results suggest that the phosphorylation of synaptic proteins on tyrosine residues may be involved in the regulation or modulation of synaptic activity.
Collapse
Affiliation(s)
- S Woodrow
- Department of Biochemistry, University of Toronto, West Hill, Ontario, Canada
| | | | | |
Collapse
|
9
|
Hanissian SH, Chatila T, Sahyoun NE. Association of neuronal pp60c-src with growth cone glycoproteins of rat brain. JOURNAL OF NEUROBIOLOGY 1992; 23:803-13. [PMID: 1279117 DOI: 10.1002/neu.480230703] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Tyrosine phosphorylation and protein tyrosine kinase (PTK) activity in the growth cone membrane-associated glycoprotein (GCGP) fraction of 1-day-old rat brain were examined. Using immunoblotting and immunoprecipitation techniques, pp60c-src was identified as one of the major PTKs associated with GCGPs. Furthermore, only GCGP-associated src that was also tyrosine phosphorylated was active. Immunoprecipitation experiments using various src antibodies revealed that pp60c-src contributed partially to the PTK activity detected in GCGPs, and that it is associated with several proteins of Mr 140 K, 120 K, 85 K and 50 K. This association of src protein with GCGPs was specific, and another src family member p59fyn, which is also abundant in the brain, did not exhibit such an association. In addition to pp60c-src, the GCGP fraction contained several major phosphotyrosine-containing proteins of Mr 140 K, and a 97/90 K doublet that corresponded to the beta subunits of IGF-I/insulin receptors. These studies show that pp60c-src associated with GCGPs is an active PTK that could be involved in neuronal growth and development, transmembrane signalling, and in recognition and/or adhesive events.
Collapse
Affiliation(s)
- S H Hanissian
- Department of Cell Biology, Burroughs Wellcome Co., Research Triangle Park, North Carolina 27709
| | | | | |
Collapse
|
10
|
Hanissian SH, Sahyoun N. Neuronal protein tyrosine kinases associated with synaptosomal glycoproteins. J Neurosci Res 1992; 32:576-82. [PMID: 1527803 DOI: 10.1002/jnr.490320413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Protein tyrosine kinase (PTK) activity associated with synaptosomal membrane glycoprotein (SMGP) fractions of rat brain was examined. The synthetic substrate poly(Glu4-Tyr) was phosphorylated by SMGP in the presence of Mg2+ and Mn2+, whose stimulatory effects were additive. In contrast, endogenous tyrosine phosphorylation in SMGPs was strictly dependent on Mn2+. Anti-phosphotyrosine antibodies (PY20) immunoprecipitated two polypeptides in SMGPs of Mr 170K and 60K. Upon preincubation with IGF-I, 97/90K polypeptides were phosphorylated, corresponding to the IGF-I receptor beta-subunits, and were immunoprecipitated with both PY20 and anti-IGF-I-receptor antibodies. Immunoblot analysis using anti-src antibody revealed that there was src protein associated with the glycoprotein fractions of solubilized synaptosomal membranes. Additional experiments revealed that the 60K tyrosine-phosphorylated polypeptide present in the PY20 precipitates was indeed pp60c-src. This was confirmed by subjecting the PY20 immunoprecipitates to immunoblotting using anti-src antibodies. In addition, src protein was directly immunoprecipitated by anti-src antibodies from the SMGP preparations. Hence, IGF-I receptors and glycoprotein-associated PTKs including pp60c-src may play an important role in synaptic transmembrane signalling, plasticity, and neuronal survival.
Collapse
Affiliation(s)
- S H Hanissian
- Department of Cell Biology, Burroughs Wellcome Co., Research Triangle Park, North Carolina 27709
| | | |
Collapse
|
11
|
Girault JA, Chamak B, Bertuzzi G, Tixier H, Wang JK, Pang DT, Greengard P. Protein phosphotyrosine in mouse brain: developmental changes and regulation by epidermal growth factor, type I insulin-like growth factor, and insulin. J Neurochem 1992; 58:518-28. [PMID: 1370320 DOI: 10.1111/j.1471-4159.1992.tb09751.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using antiphosphotyrosine antibodies, we have investigated protein phosphorylation in mouse brain during development in intact animals and in reaggregated cerebral cultures. Under basal conditions, in vivo and in vitro, the levels of two main phosphoproteins, of Mr 120,000 and 180,000 (pp180), increased with development, reaching a maximum in the early postnatal period and decreasing thereafter. In adult forebrain, pp180 was still highly phosphorylated, but it was not detected in cerebellum or in peripheral tissues. In reaggregated cortical cultures, epidermal growth factor (EGF), type I insulin-like growth factor (IGF-I), and insulin enhanced protein tyrosine phosphorylation of several proteins, which were specific for EGF or IGF-I/insulin. In highly enriched neuronal or astrocytic monolayer cultures, some proteins phosphorylated in basal conditions, or in response to EGF and IGF-I, were found in both types of culture, whereas others appeared cell type specific. In addition, in each cell type, some proteins were phosphorylated under the action of both growth factors. These results indicate that tyrosine protein phosphorylation is maximal in mouse brain during development and is regulated by growth factors in neurons as well as in astrocytes.
Collapse
Affiliation(s)
- J A Girault
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, New York
| | | | | | | | | | | | | |
Collapse
|
12
|
Cudmore SB, Gurd JW. Postnatal age and protein tyrosine phosphorylation at synapses in the developing rat brain. J Neurochem 1991; 57:1240-8. [PMID: 1895104 DOI: 10.1111/j.1471-4159.1991.tb08285.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The relationship between postnatal age and protein tyrosine kinase activity in synaptosomes prepared from the rat forebrain was studied. Synaptosomal particulate and soluble fractions, as well as total homogenates, the cell soluble fraction, and P3, were prepared from rats ranging in postnatal age from 5 to 60 days and analyzed for (a) tyrosine kinase activity using polyglutamyltyrosine (4:1) as the substrate, (b) the presence of endogenous substrates for tyrosine phosphorylation using polyclonal antibodies specific for phosphotyrosine, and (c) levels of pp60src. Enzyme activity, expressed per milligram of protein, in the total homogenate, P3, and both the cell and synaptosomal soluble fractions was highest in the brains of young animals (postnatal days 5-10) and decreased thereafter to adult levels. In contrast, tyrosine kinase activity in the synaptosomal particulate fraction exhibited a unique biphasic developmental profile, increasing to maxima at postnatal days 10 and 20 before decreasing to adult values. Endogenous substrates for tyrosine phosphorylation were identified by incubating subcellular fractions with 2 mM ATP in the presence of sodium orthovanadate and probing nitrocellulose blots of proteins separated by gel electrophoresis with antiphosphotyrosine antibodies. Several phosphotyrosine-containing proteins were detected in the synaptosomal particulate and P3 fractions, including proteins of Mr 180K, 145K, 120K, 100K, 77K, 68K, 62K, 54K, 52K, and 42K. In the cell soluble fraction a protein doublet of Mr 54/52K and a 120K protein were the major phosphotyrosine-containing proteins. The 54/52K doublet was the major protein tyrosine kinase substrate in the synaptosomal soluble fraction.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- S B Cudmore
- Department of Biochemistry, University of Toronto, Ontario, Canada
| | | |
Collapse
|
13
|
Igarashi M, Komiya Y. Tyrosine phosphorylation and immunodetection of vinculin in growth cone particle (GCP) fraction and in GCP-cytoskeletal subfractions. J Neurosci Res 1991; 30:266-74. [PMID: 1724470 DOI: 10.1002/jnr.490300127] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The growth cone, the motile tip of developing neuronal processes, is considered responsible for the exact guidance of axons and synaptogenesis. High activity of tyrosine kinases in growth cones may contribute to the functions of growth cones. Our previous work revealed that vinculin is one of the endogenous substrates for intrinsic tyrosine kinases in the growth cone particle (GCP) fraction isolated from fetal rat brain. In the present study, we examined tyrosine phosphorylation and immunoblot analysis of vinculin in various fractions from fetal rat brains and adult synaptosomal fraction. Tyrosine phosphorylation of vinculin in the GCP fraction was more prominent than in any other fraction from fetal brain or synaptosomes from adult. Compared to other fractions, however, the enrichment of vinculin in the GCP fraction was not observed. Tyrosine phosphorylation of vinculin in the fraction was inhibited by genistein, a specific tyrosine kinase inhibitor. Although vinculin was also phosphorylated by protein kinase C in the GCP fraction, it incorporated a much smaller amount of 32P than MARCKS protein or GAP-43. The cytoskeletal subfraction from the GCP fraction contained a considerable amount of vinculin and it was one of the major substrates for tyrosine kinases in the GCP cytoskeleton. The membrane skeleton from the GCP fraction contained a low amount of vinculin but showed high kinase activity that phosphorylated vinculin. Taken together, our results suggest that tyrosine phosphorylation of vinculin contributes to the cytoskeletal organization of growth cones.
Collapse
Affiliation(s)
- M Igarashi
- Department of Molecular and Cellular Neurobiology, Gunma University School of Medicine, Maebashi, Japan
| | | |
Collapse
|
14
|
Lu WX, Chang KJ. Insulin-like growth factor-1 and dibutyryl CAMP induce differentiation and decrease opioid receptor binding activity in N4TG1 neuroblastoma cells. Mol Cell Neurosci 1991; 2:284-93. [DOI: 10.1016/1044-7431(91)90057-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/1991] [Indexed: 11/15/2022] Open
|
15
|
Igarashi M, Saito S, Komiya Y. Vinculin is one of the major endogenous substrates for intrinsic tyrosine kinases in neuronal growth cones isolated from fetal rat brain. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 193:551-8. [PMID: 2121482 DOI: 10.1111/j.1432-1033.1990.tb19371.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neuronal growth cones, the motile tips of growing neuronal processes, are responsible for the exact guidance of extending neurites. To elucidate the mechanisms of their biochemical signal transduction in growth cones, the growth-cone-enriched fraction was isolated biochemically from fetal rat brain and the endogenous protein phosphorylation in the fraction was analyzed under the conditions where tyrosine residues were preferentially phosphorylated. One of the major phosphoproteins was a 130-kDa slightly acidic protein which reacted with antiphosphotyrosine antibody. Its phosphoryl residues were alkali-stable. Thus, the 130-kDa protein was concluded to be susceptible to tyrosine phosphorylation. This protein was a component of cytoskeletal proteins thought to be associated indirectly with membranes. All the behavior of the 130-kDa protein was compatible with the properties of vinculin, a component of focal contacts which are responsible for the stable or motile adhesion between cells or between a cell and the substratum. Immunochemical analyses showed that the 130-kDa protein was specifically recognized by anti-vinculin antibody. Therefore, the 130-kDa protein was concluded to be vinculin. Tyrosine phosphorylation of the protein appeared to be relatively more pronounced in the growth-cone-enriched fraction than in adult synaptosomes. The results suggest that tyrosine phosphorylation of vinculin may be regulated developmentally and it may be involved in the functions of growth cones.
Collapse
Affiliation(s)
- M Igarashi
- Department of Biochemistry, Jichi Medical School, Tochigi, Japan
| | | | | |
Collapse
|
16
|
Edmonds BT, Moomaw CR, Hsu JT, Slaughter C, Ellis L. The p38 and p34 polypeptides of growth cone particle membranes are the alpha- and beta-subunits of G proteins. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1990; 56:131-6. [PMID: 2126227 DOI: 10.1016/0165-3806(90)90172-u] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Growth cone particle (GCP) membranes prepared from fetal day 17 rat brain are comprised of 5 major polypeptides as analyzed by SDS-PAGE: tubulin (p52), actin (p42), pp46/GAP-43 and two unidentified species, p38 and p34. Antibodies specific for the alpha- and beta-subunits of G proteins recognize p38 and p34, respectively, on immunoblots following one- and two-dimensional electrophoretic separation. That G protein subunits comprise major species of GCP membrane-associated polypeptides suggests a role for G proteins in transmembrane signaling in nerve growth cones.
Collapse
Affiliation(s)
- B T Edmonds
- Howard Hughes Medical Institute, University of Texas Southwestern Medical School, Dallas 75235-9050
| | | | | | | | | |
Collapse
|