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Regulation of the filament structure and assembly of Acanthamoeba myosin II by phosphorylation of serines in the heavy-chain nonhelical tailpiece. Proc Natl Acad Sci U S A 2012; 110:E33-40. [PMID: 23248285 DOI: 10.1073/pnas.1219727110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acanthamoeba myosin II (AMII) has two heavy chains ending in a 27-residue nonhelical tailpiece and two pairs of light chains. In a companion article, we show that five, and only five, serine residues can be phosphorylated both in vitro and in vivo: Ser639 in surface loop 2 of the motor domain and serines 1489, 1494, 1499, and 1504 in the nonhelical tailpiece of the heavy chains. In that paper, we show that phosphorylation of Ser639 down-regulates the actin-activated MgATPase activity of AMII and that phosphorylation of the serines in the nonhelical tailpiece has no effect on enzymatic activity. Here we show that bipolar tetrameric, hexameric, and octameric minifilaments of AMII with the nonhelical tailpiece serines either phosphorylated or mutated to glutamate have longer bare zones and more tightly clustered heads than minifilaments of unphosphorylated AMII, irrespective of the phosphorylation state of Ser639. Although antiparallel dimers of phosphorylated and unphosphorylated myosins are indistinguishable, phosphorylation inhibits dimerization and filament assembly. Therefore, the different structures of tetramers, hexamers, and octamers of phosphorylated and unphosphorylated AMII must be caused by differences in the longitudinal stagger of phosphorylated and unphosphorylated bipolar dimers and tetramers. Thus, although the actin-activated MgATPase activity of AMII is regulated by phosphorylation of Ser639 in loop 2 of the motor domain, the structure of AMII minifilaments is regulated by phosphorylation of one or more of four serines in the nonhelical tailpiece of the heavy chain.
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2
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Myosin II isoform switching mediates invasiveness after TGF-β-induced epithelial-mesenchymal transition. Proc Natl Acad Sci U S A 2011; 108:17991-6. [PMID: 22025714 DOI: 10.1073/pnas.1106499108] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Despite functional significance of nonmuscle myosin II in cell migration and invasion, its role in epithelial-mesenchymal transition (EMT) or TGF-β signaling is unknown. Analysis of normal mammary gland expression revealed that myosin IIC is expressed in luminal cells, whereas myosin IIB expression is up-regulated in myoepithelial cells that have more mesenchymal characteristics. Furthermore, TGF-β induction of EMT in nontransformed murine mammary gland epithelial cells results in an isoform switch from myosin IIC to myosin IIB and increased phosphorylation of myosin heavy chain (MHC) IIA on target sites known to regulate filament dynamics (S1916, S1943). These expression and phosphorylation changes are downstream of heterogeneous nuclear ribonucleoprotein-E1 (E1), an effector of TGF-β signaling. E1 knockdown drives cells into a migratory, invasive mesenchymal state and concomitantly up-regulates MHC IIB expression and MHC IIA phosphorylation. Abrogation of myosin IIB expression in the E1 knockdown cells has no effect on 2D migration but significantly reduced transmigration and macrophage-stimulated collagen invasion. These studies indicate that transition between myosin IIC/myosin IIB expression is a critical feature of EMT that contributes to increases in invasive behavior.
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3
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Betapudi V, Gokulrangan G, Chance MR, Egelhoff TT. A proteomic study of myosin II motor proteins during tumor cell migration. J Mol Biol 2011; 407:673-86. [PMID: 21316371 DOI: 10.1016/j.jmb.2011.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 02/01/2011] [Accepted: 02/03/2011] [Indexed: 10/24/2022]
Abstract
Myosin II motor proteins play important roles in cell migration. Although myosin II filament assembly plays a key role in the stabilization of focal contacts at the leading edge of migrating cells, the mechanisms and signaling pathways regulating the localized assembly of lamellipodial myosin II filaments are poorly understood. We performed a proteomic analysis of myosin heavy chain (MHC) phosphorylation sites in MDA-MB 231 breast cancer cells to identify MHC phosphorylation sites that are activated during integrin engagement and lamellar extension on fibronectin. Fibronectin-activated MHC phosphorylation was identified on novel and previously recognized consensus sites for phosphorylation by protein kinase C and casein kinase II (CK-II). S1943, a CK-II consensus site, was highly phosphorylated in response to matrix engagement, and phosphoantibody staining revealed phosphorylation on myosin II assembled into leading-edge lamellae. Surprisingly, neither pharmacological reduction nor small inhibitory RNA reduction in CK-II activity reduced this stimulated S1943 phosphorylation. Our data demonstrate that S1943 phosphorylation is upregulated during lamellar protrusion, and that CK-II does not appear to be the kinase responsible for this matrix-induced phosphorylation event.
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Affiliation(s)
- Venkaiah Betapudi
- Department of Cell Biology, Lerner College of Medicine, Case Western Reserve University, The Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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4
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Komatsu S, Ikebe M. The phosphorylation of myosin II at the Ser1 and Ser2 is critical for normal platelet-derived growth factor induced reorganization of myosin filaments. Mol Biol Cell 2007; 18:5081-90. [PMID: 17928407 DOI: 10.1091/mbc.e06-12-1076] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phosphorylation of the regulatory light chain of myosin II (MLC(20)) at the activation sites promotes both the motor activity and the filament formation of myosin II, thus playing an important role in various cell motile processes. In contrast, the physiological function of phosphorylation of MLC(20) at the inhibitory sites is unknown. Here we report for the first time the function of the inhibitory site phosphorylation in the cells. We successfully produced the antibodies specifically recognizing the phosphorylation sites of MLC(20) at Ser1, and the platelet-derived growth factor (PDGF)-induced change in the phosphorylation at the Ser1 was monitored. The phosphorylation of MLC(20) at the Ser1 significantly increased during the PDGF-induced actin cytoskeletal reorganization. PDGF disassembled the stress fibers, and this was attenuated with the expression of unphosphorylatable MLC(20) at the Ser1/Ser2 phosphorylation sites. The present results suggest that the down-regulation of myosin II activity achieved by the phosphorylation at the Ser1/Ser2 sites plays an important role in the normal reorganization of actomyosin filaments triggered by PDGF receptor stimulation.
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Affiliation(s)
- Satoshi Komatsu
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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5
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Sato MK, Takahashi M, Yazawa M. Two regions of the tail are necessary for the isoform-specific functions of nonmuscle myosin IIB. Mol Biol Cell 2007; 18:1009-17. [PMID: 17202408 PMCID: PMC1805092 DOI: 10.1091/mbc.e06-08-0706] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
To function in the cell, nonmuscle myosin II molecules assemble into filaments through their C-terminal tails. Because myosin II isoforms most likely assemble into homo-filaments in vivo, it seems that some self-recognition mechanisms of individual myosin II isoforms should exist. Exogenous expression of myosin IIB rod fragment is thus expected to prevent the function of myosin IIB specifically. We expected to reveal some self-recognition sites of myosin IIB from the phenotype by expressing appropriate myosin IIB rod fragments. We expressed the C-terminal 305-residue rod fragment of the myosin IIB heavy chain (BRF305) in MRC-5 SV1 TG1 cells. As a result, unstable morphology was observed like MHC-IIB(-/-) fibroblasts. This phenotype was not observed in cells expressing BRF305 mutants: 1) with a defect in assembling, 2) lacking N-terminal 57 residues (N-57), or 3) lacking C-terminal 63 residues (C-63). A myosin IIA rod fragment ARF296 corresponding to BRF305 was not effective. However, the chimeric ARF296, in which the N-57 and C-63 of BRF305 were substituted for the corresponding regions of ARF296, acquired the ability to induce unstable morphology. We propose that the N-57 and C-63 of BRF305 are involved in self-recognition when myosin IIB molecules assemble into homo-filament.
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Affiliation(s)
- Masaaki K. Sato
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Masayuki Takahashi
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Michio Yazawa
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810 Japan
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6
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Ludowyke RI, Elgundi Z, Kranenburg T, Stehn JR, Schmitz-Peiffer C, Hughes WE, Biden TJ. Phosphorylation of nonmuscle myosin heavy chain IIA on Ser1917 is mediated by protein kinase C beta II and coincides with the onset of stimulated degranulation of RBL-2H3 mast cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:1492-9. [PMID: 16849455 DOI: 10.4049/jimmunol.177.3.1492] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dynamic remodeling of the actinomyosin cytoskeleton is integral to many biological processes. It is regulated, in part, by myosin phosphorylation. Nonmuscle myosin H chain IIA is phosphorylated by protein kinase C (PKC) on Ser(1917). Our aim was to determine the PKC isoform specificity of this phosphorylation event and to evaluate its potential role in regulated secretion. Using an Ab against the phosphorylated form of Ser(1917), we show that this site is not phosphorylated in unstimulated RBL-2H3 mast cells. The physiological stimulus, Ag, or the pharmacological activators, PMA plus A23187, induced Ser(1917) phosphorylation with a time course coincident with the onset of granule mediator secretion. Dephosphorylation at this site occurred as Ag-stimulated secretion declined from its peak, but dephosphorylation was delayed in cells activated with PMA plus A23187. Phosphate incorporation was also enhanced by PMA alone and by inhibition of protein phosphatase 2A. Gö6976, an inhibitor of conventional PKC isoforms, abolished secretion and Ser(1917) phosphorylation with similar dose dependencies consistent with involvement of either PKCalpha or PKCbeta. Phorbol ester-stimulated Ser(1917) phosphorylation was reconstituted in HEK-293 cells (which lack endogenous PKCbeta) by overexpression of both wild-type and constitutively active PKCbetaII but not the corresponding PKCbetaI or PKCalpha constructs. A similar selectivity for PKCbetaII overexpression was also observed in MIN6 insulinoma cells infected with recombinant PKC wild-type adenoviruses. Our results implicate PKC-dependent phosphorylation of myosin H chain IIA in the regulation of secretion in mast cells and suggest that Ser(1917) phosphorylation might be a marker of PKCbetaII activation in diverse cell types.
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Affiliation(s)
- Russell I Ludowyke
- Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, Australia
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Rosenberg M, Ravid S. Protein kinase Cgamma regulates myosin IIB phosphorylation, cellular localization, and filament assembly. Mol Biol Cell 2006; 17:1364-74. [PMID: 16394101 PMCID: PMC1382324 DOI: 10.1091/mbc.e05-07-0597] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Nonmuscle myosin II is an important component of the cytoskeleton, playing a major role in cell motility and chemotaxis. We have previously demonstrated that, on stimulation with epidermal growth factor (EGF), nonmuscle myosin heavy chain II-B (NMHC-IIB) undergoes a transient phosphorylation correlating with its cellular localization. We also showed that members of the PKC family are involved in this phosphorylation. Here we demonstrate that of the two conventional PKC isoforms expressed by prostate cancer cells, PKCbetaII and PKCgamma, PKCgamma directly phosphorylates NMHC-IIB. Overexpression of wild-type and kinase dead dominant negative PKCgamma result in both altered NMHC-IIB phosphorylation and subcellular localization. We have also mapped the phosphorylation sites of PKCgamma on NMHC-IIB. Conversion of the PKCgamma phosphorylation sites to alanine residues, reduces the EGF-dependent NMHC-IIB phosphorylation. Aspartate substitution of these sites reduces NMHC-IIB localization into cytoskeleton. These results indicate that PKCgamma regulates NMHC-IIB phosphorylation and cellular localization in response to EGF stimulation.
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Affiliation(s)
- Michael Rosenberg
- Department of Biochemistry, Institute of Medical Sciences, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel
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8
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Kohlstedt K, Kellner R, Busse R, Fleming I. Signaling via the angiotensin-converting enzyme results in the phosphorylation of the nonmuscle myosin heavy chain IIA. Mol Pharmacol 2005; 69:19-26. [PMID: 16186248 DOI: 10.1124/mol.105.016733] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The phosphorylation of the short C-terminal cytoplasmic domain of the somatic angiotensin-converting enzyme (ACE) is involved in the regulation of enzyme shedding. We determined whether the phosphorylation of the cytoplasmic domain of ACE (ACEct) on Ser1270 regulates the cleavage/secretion of the enzyme by affecting its association with other proteins. ACE was associated with beta-actin and the nonmuscle myosin heavy chain IIA (MYH9) in endothelial cells, as determined by coimmunoprecipitation experiments as well as an ACEct affinity column. The ACE-associated MYH9 immunoprecipitated from (32)P-labeled endothelial cells was basally phosphorylated and cell stimulation with ACE inhibitors, or with bradykinin, increased the phosphorylation of MYH9. Casein kinase 2 (CK2) but not protein kinase C phosphorylated MYH9 in vitro, CK2 coprecipitated with MYH9 from endothelial cells and the phosphorylation of MYH9 in intact cells paralleled the phosphorylation of ACE on Ser1270 by CK2. The CK2 inhibitor 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole attenuated the phosphorylation of ACE and MYH9, disrupted their association, and enhanced the cleavage/secretion of ACE from the plasma membrane. Cytochalasin D decreased the interaction between ACE and MYH9 and stimulated ACE shedding. Although MYH9 was still able to associate with residual amounts of a nonphosphorylatable S1270A ACE mutant, no ACE inhibitor-induced increase in MYH9 phosphorylation could be detected in S1270A-expressing cells. These data indicate that the interaction of ACE with MYH9 determines ACE shedding and is modulated by phosphorylation processes. Furthermore, because ACE inhibitors affect the phosphorylation of MYH9, the phosphorylation of this class II myosin might contribute to the phenomenon of ACE signaling in endothelial cells.
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Affiliation(s)
- Karin Kohlstedt
- Vascular Signaling Group, Institut für Kardiovaskuläre Physiologie, Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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9
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Abstract
In addition to important roles near the actin-rich cell cortex, ample evidence indicates that multiple myosins are also involved in membrane movements in the endomembrane system. Nonmuscle myosin-II has been shown to have roles in anterograde and retrograde trafficking at the Golgi. Myosin-II is present on Golgi stacks isolated from intestinal epithelial cells and has been localized to the Golgi in several polarized and unpolarized cell lines. An understanding of roles of myosin-II in Golgi physiology will be facilitated by understanding the molecular arrangement of myosin-II at the Golgi. Salt-washing removes endogenous myosin-II from isolated Golgi and purified brush border myosin-II can bind in vitro. Brush border myosin-II binds to a tightly bound Golgi peripheral membrane protein with a K(1/2) of 75 nM and binding is saturated at 0.7 pmol myosin/microg Golgi. Binding studies using papain cleavage fragments of brush border myosin-II show that the 120-kDa rod domain, but not the head domain, of myosin heavy chain can bind directly to Golgi stacks. The 120-kDa domain does not bind to Golgi membranes when phosphorylated in vitro with casein kinase-II. These results suggest that phosphorylation in the rod domain may regulate the binding and/or release of myosin-II from the Golgi. These data support a model in which myosin-II is tethered to the Golgi membrane by its tail and actin filaments by its head. Thus, translocation along actin filaments may extend Golgi membrane tubules and/or vesicles away from the Golgi complex.
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Affiliation(s)
- Karl R Fath
- Biology Department, Queens College and Graduate Center of the City University of New York, Flushing, NY 11367, USA.
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Dulyaninova NG, Malashkevich VN, Almo SC, Bresnick AR. Regulation of myosin-IIA assembly and Mts1 binding by heavy chain phosphorylation. Biochemistry 2005; 44:6867-76. [PMID: 15865432 DOI: 10.1021/bi0500776] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previous studies suggested that heavy chain phosphorylation regulates non-muscle myosin-II assembly in an isoform-specific manner, affecting the assembly of myosin-IIB, but not myosin-IIA. We re-examined the effects of heavy chain phosphorylation on myosin-IIA filament formation and also examined mts1 binding. We demonstrated that heavy chain phosphorylation by either protein kinase C (PKC) or casein kinase 2 (CK2) inhibits the assembly of myosin-IIA into filaments. PKC phosphorylation had no affect on mts1 binding, but CK2 phosphorylation decreased the affinity of mts1 for the myosin-IIA rod by approximately 6.5-fold. Mts1 destabilized PKC-phosphorylated myosin-IIA filaments and inhibited the assembly of myosin-IIA monomers with maximal inhibition of assembly and promotion of disassembly occurring at a molar ratio of one mts1 dimer per myosin-IIA rod. At this molar ratio, mts1 only weakly disassembled CK2-phosphorylated myosin-IIA filaments and weakly inhibited the assembly of CK2-phosphorylated myosin-IIA monomers. These observations demonstrate that CK2 phosphorylation of the myosin-IIA heavy chain protects against mts1-induced filament disassembly and inhibition of assembly, and suggest that heavy chain phosphorylation provides an additional level of regulation for the mts1-myosin-IIA interaction.
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Affiliation(s)
- Natalya G Dulyaninova
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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11
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Sokac AM, Bement WM. Regulation and expression of metazoan unconventional myosins. INTERNATIONAL REVIEW OF CYTOLOGY 2001; 200:197-304. [PMID: 10965469 DOI: 10.1016/s0074-7696(00)00005-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Unconventional myosins are molecular motors that convert adenosine triphosphate (ATP) hydrolysis into movement along actin filaments. On the basis of primary structure analysis, these myosins are represented by at least 15 distinct classes (classes 1 and 3-16), each of which is presumed to play a specific cellular role. However, in contrast to the conventional myosins-2, which drive muscle contraction and cytokinesis and have been studied intensively for many years in both uni- and multicellular organisms, unconventional myosins have only been subject to analysis in metazoan systems for a short time. Here we critically review what is known about unconventional myosin regulation, function, and expression. Several points emerge from this analysis. First, in spite of the high relative conservation of motor domains among the myosin classes, significant differences are found in biochemical and enzymatic properties of these motor domains. Second, the idea that characteristic distributions of unconventional myosins are solely dependent on the myosin tail domain is almost certainly an oversimplification. Third, the notion that most unconventional myosins function as transport motors for membranous organelles is challenged by recent data. Finally, we present a scheme that clarifies relationships between various modes of myosin regulation.
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Affiliation(s)
- A M Sokac
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison 53706, USA
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12
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Kriajevska M, Bronstein IB, Scott DJ, Tarabykina S, Fischer-Larsen M, Issinger O, Lukanidin E. Metastasis-associated protein Mts1 (S100A4) inhibits CK2-mediated phosphorylation and self-assembly of the heavy chain of nonmuscle myosin. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1498:252-63. [PMID: 11108967 DOI: 10.1016/s0167-4889(00)00100-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A role for EF-hand calcium-binding protein Mts1 (S100A4) in the phosphorylation and the assembly of myosin filaments was studied. The nonmuscle myosin molecules form bipolar filaments, which interact with actin filaments to produce a contractile force. Phosphorylation of the myosin plays a regulatory role in the myosin assembly. In the presence of calcium, Mts1 binds at the C-terminal end of the myosin heavy chain close to the site of phosphorylation by protein kinase CK2 (Ser1944). In the present study, we have shown that interaction of Mts1 with the human platelet myosin or C-terminal fragment of the myosin heavy chain inhibits phosphorylation of the myosin heavy chain by protein kinase CK2 in vitro. Mts1 might also bind directly the beta subunit of protein kinase CK2, thereby modifying the enzyme activity. Our results indicate that myosin oligomers were disassembled in the presence of Mts1. The short C-terminal fragment of the myosin heavy chain was totally soluble in the presence of an equimolar amount of Mts1 at low ionic conditions (50 mM NaCl). Depolymerization was found to be calcium-dependent and could be blocked by EGTA. Our data suggest that Mts1 can increase myosin solubility and therefore suppress its assembly.
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Affiliation(s)
- M Kriajevska
- Department of Molecular Cancer Biology, Institute of Cancer Biology, Danish Cancer Society, Copenhagen, Denmark
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13
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Abstract
Myosins constitute a large superfamily of actin-dependent molecular motors. Phylogenetic analysis currently places myosins into 15 classes. The conventional myosins which form filaments in muscle and non-muscle cells form class II. There has been extensive characterization of these myosins and much is known about their function. With the exception of class I and class V myosins, little is known about the structure, enzymatic properties, intracellular localization and physiology of most unconventional myosin classes. This review will focus on myosins from class IV, VI, VII, VIII, X, XI, XII, XIII, XIV and XV. In addition, the function of myosin II in non-muscle cells will also be discussed.
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Affiliation(s)
- J R Sellers
- National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room 8N202, Bethesda, MD 20892, USA.
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14
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Abstract
Myosin II, the conventional two-headed myosin that forms bipolar filaments, is directly involved in regulating cytokinesis, cell motility and cell morphology in nonmuscle cells. To understand the mechanisms by which nonmuscle myosin-II regulates these processes, investigators are now looking at the regulation of this molecule in vertebrate nonmuscle cells. The identification of multiple isoforms of nonmuscle myosin-II, whose activities and regulation differ from that of smooth muscle myosin-II, suggests that, in addition to regulatory light chain phosphorylation, other regulatory mechanisms control vertebrate nonmuscle myosin-II activity.
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Affiliation(s)
- A R Bresnick
- Department of Biochemistry Albert Einstein College of Medicine 1300 Morris Park Avenue Bronx NY 10461 USA.
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15
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Wylie SR, Wu PJ, Patel H, Chantler PD. A conventional myosin motor drives neurite outgrowth. Proc Natl Acad Sci U S A 1998; 95:12967-72. [PMID: 9789024 PMCID: PMC23673 DOI: 10.1073/pnas.95.22.12967] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/1998] [Indexed: 11/18/2022] Open
Abstract
Neuritic outgrowth is a striking example of directed motility, powered through the actions of molecular motors. Members of the myosin superfamily of actin-associated motors have been implicated in this complex process. Although conventional myosin II is known to be present in neurons, where it is localized at the leading edge of growth cones and in the cell cortex close to the plasma membrane, its functional involvement in growth cone motility has remained unproven. Here, we show that antisense oligodeoxyribonucleotides, complementary to a specific isoform of conventional myosin (myosin IIB), attenuate filopodial extension whereas sense and scrambled control oligodeoxyribonucleotides have no effect. Attenuation is shown to be reversible, neurite outgrowth being restored after cessation of the antisense regimen. Myosin IIB mRNA was present during active neurite extension, but levels were minimal in phenotypically rounded cells before neurite outgrowth and message levels decreased during antisense treatment. By contrast, the myosin IIA isoform is shown to be expressed constitutively both before and during neurite outgrowth and throughout exposure to myosin IIB antisense oligodeoxyribonucleotides. These results provide direct evidence that a conventional two-headed myosin is required for growth cone motility and is responsible, at least in part, for driving neuritic process outgrowth.
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Affiliation(s)
- S R Wylie
- Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, United Kingdom
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16
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Murakami N, Chauhan VP, Elzinga M. Two nonmuscle myosin II heavy chain isoforms expressed in rabbit brains: filament forming properties, the effects of phosphorylation by protein kinase C and casein kinase II, and location of the phosphorylation sites. Biochemistry 1998; 37:1989-2003. [PMID: 9485326 DOI: 10.1021/bi971959a] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the course of the expression of a 47-kDa COOH-terminal fragment of brain-type nonmuscle myosin heavy chain (MIIBF47), we found two closely related forms of MIIB, designated MIIB alpha and MIIB beta, in rabbit brains. The B alpha form corresponded to SMemb, described by Kuro-o et al. [(1991) J. Biol. Chem. 266, 3768] and was the more abundant form in rabbit brain, while the B beta form was novel. MIIB beta F47 differed from MIIB alpha F47 at six positions, three of which were within the carboxyl-terminal nonhelical domain; in MIIB beta F47, Ser, Pro, and Lys replaced Pro, Ser, and Glu, respectively. MIIB alpha F47 and MIIB beta F47 differed in filament assembly properties in the presence of various concentrations of salt, and a chimera containing the helical domain of MIIB beta F47 and the nonhelical domain of MIIB alpha F47 behaved very much like MIIB beta F47. Protein kinase C (PK C) incorporated 1 and 2 mol of phosphate/mol peptide of MIIB alpha F47 and MIIB beta F47, respectively, and caused similar levels of inhibition of assembly for both isoforms. Casein kinase II (CK II) incorporated 4 and 2 mol of phosphate/mol of MIIB alpha F47 and MIIB beta F47 peptides, respectively, and this caused strong inhibition of assembly for MIIB alpha F47 but only slight inhibition for MIIB beta F47. PK C sites in MIIB alpha F47 were localized within a region containing a cluster of Ser residues near the predicted junction of the helical and nonhelical domains: P-I-S(PO4)-F-S(PO4)-S(PO4)-S(PO4)-R-S(PO4)-. Out of the five potential PK C sites, only one site seemed to be phosphorylated per peptide. The PK C sites in MIIB beta F47 were localized as S(PO4)-I-S-F-S-S-(PO4)-R-S(PO4)-, with total incorporation of about 2 mol/mol of peptide. In addition, PK C phosphorylated a Ser within the predicted helical domain, E-V-S(PO4)-T-L, in both MIIB alpha F47 and MIIB beta F47. For CK II, five sites were identified within the COOH end of MIIB alpha F47: S(PO4)-L-E-L-S(PO4)-D-D-D-T(PO4)-E-S-K-T-S(PO4)-D-V-N-E-T-Q-P-P-Q-S(PO4) -E. The same sites were phosphorylated in MIIB beta F47 except for the first Ser, which was replaced by Pro in MIIB beta F47. An average of about two of the four potential sites were phosphorylated in MIIB beta F47, while in MIIB alpha F47 all five sites could be fully phosphorylated by CK II. Our results demonstrate that (1) the helical domains dictate the intrinsic salt dependence of assembly for nonmuscle myosin, (2) the isoforms are phosphorylatable by different kinases in an isoform specific manner mostly within the COOH-terminal nonhelical domain, and (3) the effects of the phosphorylation on assembly are isoform specific.
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Affiliation(s)
- N Murakami
- Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, USA.
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17
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Meer DP, Eddinger TJ. Expression of smooth muscle myosin heavy chains and unloaded shortening in single smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1259-66. [PMID: 9357770 DOI: 10.1152/ajpcell.1997.273.4.c1259] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The functional significance of the variable expression of the smooth muscle myosin heavy chain (SM-MHC) tail isoforms, SM1 and SM2, was examined at the mRNA level (which correlates with the protein level) in individual permeabilized rabbit arterial smooth muscle cells (SMCs). The length of untethered single permeabilized SMCs was monitored during unloaded shortening in response to increased Ca2+ (pCa 6.0), histamine (1 microM), and phenylephrine (1 microM). Subsequent to contraction, the relative expression of SM1 and SM2 mRNAs from the same individual SMCs was determined by reverse transcription-polymerase chain reaction amplification and densitometric analysis. Correlational analyses between the SM2-to-SM1 ratio and unloaded shortening in saponin- and alpha-toxin-permeabilized SMCs (n = 28) reveal no significant relationship between the SM-MHC tail isoform ratio and unloaded shortening velocity. The best correlations between SM2/SM1 and the contraction characteristics of untethered vascular SMCs were with the minimum length attained following contraction (n = 20 and r = 0.72 for alpha-toxin, n = 8 and r = 0.78 for saponin). These results suggest that the primary effect of variable expression of the SM1 and SM2 SM-MHC tail isoforms is on the cell final length and not on shortening velocity.
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Affiliation(s)
- D P Meer
- Department of Biology, Marquette University, Milwaukee, Wisconsin 53201-1881, USA
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18
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Choi OH, Park CS, Itoh K, Adelstein RS, Beaven MA. Cloning of the cDNA encoding rat myosin heavy chain-A and evidence for the absence of myosin heavy chain-B in cultured rat mast (RBL-2H3) cells. J Muscle Res Cell Motil 1996; 17:69-77. [PMID: 8740433 DOI: 10.1007/bf00140325] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The complete amino acid sequence (1961 amino acids) of a vertebrate cellular myosin heavy chain-A was deduced from cDNA clones of a secretory rat mast cell line, the RBL-2H3 cell. The rat, human and chicken cellular myosin heavy chain-A exhibited high similarity in domains that allow binding of ATP and actin. The amino acid sequence of non-muscle myosin heavy chain-A from rat was 96% identical to that in human and 92% identical to that in chicken. Northern blot analysis of mRNA indicated the presence of single message of 7.4 kilobases. Northern blot, reverse-transcriptase polymerase chain reaction, and Western blot with isoform-specific antibodies indicated that RBL-2H3 cells expressed exclusively myosin heavy chain-A. Unlike rat PC12 cells, as well as a wide variety of other cultured cells and tissues, myosin heavy chain-B mRNA and protein were not detectable in RBL-2H3 cells. Because RBL-2H3 cells can be stimulated to release secretory granules as well as newly generated arachidonic acid and cytokines but lack myosin heavy chain-B, this cell line may provide a unique model to study the role of myosin heavy chain-A in cellular responses to antigen and other stimulants.
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Affiliation(s)
- O H Choi
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1760, USA
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19
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Phillips CL, Yamakawa K, Adelstein RS. Cloning of the cDNA encoding human nonmuscle myosin heavy chain-B and analysis of human tissues with isoform-specific antibodies. J Muscle Res Cell Motil 1995; 16:379-89. [PMID: 7499478 DOI: 10.1007/bf00114503] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Previously, we reported the sequence of cDNA clones encoding amino acids 63 through 723 of the human nonmuscle myosin heavy chain-B isoform. In this paper, we present the derived sequence of the remaining 1303 amino acids along with 5' and 3' untranslated sequences. We made use of the differences between the derived nonmuscle myosin heavy chain-A and -B amino acid sequences to raise isoform-specific antibodies. Immunoblot analysis reveals a differential expression of both myosin heavy chain isoforms in a variety of human adult and foetal tissues and cells. When extracts of human adult aorta were subjected to gel electrophoresis, two distinct Coomassie Blue-stained bands and a fused band were seen migrating at approximately 200 kDa. These bands can be detected with four different specific antibodies recognizing the two different smooth muscle myosin heavy chain isoforms (204 kDa and 200 kDa) and the two different nonmuscle myosin heavy chain isoforms (A and B). Using immunohistochemistry, we confirmed the presence of the four different isoforms in adult and foetal aortas.
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Affiliation(s)
- C L Phillips
- Laboratory of Molecular Cardiology National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Kelley CA, Oberman F, Yisraeli JK, Adelstein RS. A Xenopus nonmuscle myosin heavy chain isoform is phosphorylated by cyclin-p34cdc2 kinase during meiosis. J Biol Chem 1995; 270:1395-401. [PMID: 7836406 DOI: 10.1074/jbc.270.3.1395] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
There are two vertebrate nonmuscle myosin heavy chain (MHC) genes that encode two separate isoforms of the heavy chain, MHC-A and MHC-B. Recent work has identified additional, alternatively spliced isoforms of MHC-B cDNA with inserted sequences of 30 nucleotides (chicken and human) or 48 nucleotides (Xenopus) at a site corresponding to the ATP binding region in the MHC protein (Takahashi, M., Kawamoto, S., and Adelstein, R.S. (1992) J. Biol. Chem. 267, 17864-17871) and Bhatia-Dey, N., Adelstein, R.S., and Dawid, I.B. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 2856-2859). The deduced amino acid sequence of these inserts contains a consensus sequence for phosphorylation by cyclin-p34cdc2 (cdc2) kinase. In cultured Xenopus XTC cells, we have identified two inserted MHC-B isoforms and a non-inserted MHC-A isoform by immunoblotting of cell extracts. When myosin was immunoprecipitated from XTC cells and phosphorylated in vitro with cdc2 kinase, the kinase catalyzed the phosphorylation of both inserted MHC-B isoforms but not MHC-A. Isoelectric focusing of tryptic peptides generated from MHC-B phosphorylated with cdc2 kinase revealed one major phosphopeptide that was purified by reverse-phase high performance liquid chromatography and sequenced. The phosphorylated residue was Ser-214, the cdc2 kinase consensus site within the insert near the ATP binding region. The same site was phosphorylated in intact XTC cells during log phase of growth and in cell-free lysates of Xenopus eggs stabilized in second meiotic metaphase but not interphase. Moreover, Ser-214 phosphorylation was detected during maturation of Xenopus oocytes when the cdc2 kinase-containing maturation-promoting factor was activated, but not in G2 interphase-arrested oocytes. These results demonstrate that MHC-B phosphorylation is tightly regulated by cdc2 kinase during meiotic cell cycles. Furthermore, MHC-A and MHC-B isoforms are differentially phosphorylated at these stages, suggesting that they may serve different functions in these cells.
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Affiliation(s)
- C A Kelley
- Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
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21
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Ojha M, Cattaneo A, Norberg W. Structure and Properties of Casein Kinase IIs from Allomyces arbuscula Phosphorylating Serine Residues. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0147-5975(06)80008-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Olcott MC, Bradley ML, Haley BE. Photoaffinity labeling of creatine kinase with 2-azido- and 8-azidoadenosine triphosphate: identification of two peptides from the ATP-binding domain. Biochemistry 1994; 33:11935-41. [PMID: 7918412 DOI: 10.1021/bi00205a032] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two different analogs of ATP, [gamma-32P]2N3ATP and and [gamma-32P]8N3ATP, were used to photoaffinity label the MM and BB isoforms of rabbit cytosolic creatine kinase. Evidence that photoinsertion was within the ATP-binding domain was as follows: (1) Assays for creatine phosphate production demonstrated that [gamma-32]2N3ATP and [gamma-32P]8N3ATP are substrates for creatine kinase. (2) Enzymatic activity was inhibited by photolabeling with either analog. (3) Saturation of photoinsertion was observed for both analogs. Half-maximal saturation was observed at 5 microM [gamma-32P]2N3ATP or 12 microM (gamma-32P]8N3ATP. (4) Photoinsertion of both probes could be decreased by micromolar levels of ATP. Immobilized Al3+ affinity chromatography and HPLC were used to isolate the peptides modified by these probes. Overlapping sequence analysis of the isolated peptides from the tryptic and chymotryptic digests of the photolabeled MM isoform revealed that [gamma-32P]8N3ATP photoinserted into the peptide region corresponding to Val279-Arg291, whereas [gamma-32P]2N3-ATP photoinserted into Val236-Lys241. The corresponding peptide (Ile279-Arg291 and Val236-Lys241) from the BB isoform were shown to be selectively modified. We conclude that amino acid residues within the peptide regions 236-241 and 279-291 of rabbit cytosolic creatine kinase are localized within the binding domain for the adenine moiety of ATP. The results also demonstrate the effectiveness and selectivity of Al3+ as the chelating agent in immobilized metal affinity chromatography for the isolation of photolabeled peptides as well as its potential to enhance retention of radiolabel during HPLC.
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Affiliation(s)
- M C Olcott
- College of Pharmacy, University of Kentucky, Lexington 40536
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23
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Direct binding of myosin II to phospholipid vesicles via tail regions and phosphorylation of the heavy chains by protein kinase C. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)33976-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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24
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Somlyo AP. Myosin isoforms in smooth muscle: how may they affect function and structure? J Muscle Res Cell Motil 1993; 14:557-63. [PMID: 8126215 DOI: 10.1007/bf00141552] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A P Somlyo
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville 22908
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25
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Chauhan A, Chauhan VP, Murakami N, Brockerhoff H, Wisniewski HM. Amyloid beta-protein stimulates casein kinase I and casein kinase II activities. Brain Res 1993; 629:47-52. [PMID: 8287280 DOI: 10.1016/0006-8993(93)90479-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Amyloid beta-protein (A beta) is the major protein of cerebrovascular and plaque amyloid in Alzheimer's disease (AD). Extensive evidence has demonstrated abnormal protein phosphorylation in this disease. We investigated the effect of synthetic A beta with the amino-acid sequence corresponding to cerebrovascular A beta and plaque A beta on the activities of casein kinase I (CK I) and casein kinase II (CK II). These enzymes were purified from bovine brain and casein was used as a substrate. A beta was found to stimulate markedly CK I- and CK II-mediated phosphorylation of casein in a concentration-dependent manner. The effect of plaque A beta was considerably higher than that of cerebrovascular A beta. Heparin, which is known to be a specific inhibitor of CK II, completely inhibited A beta-stimulated CK II activity. A beta itself was not a substrate for casein kinases. These findings were confirmed using other substrates for CK I and CK II. The experiments with synthetic CK II-substrate peptide (Leu-Glu-Leu-Ser-Asp-Asp-Asp-Asp-Glu) and the phosphorylation of erythrocyte membrane proteins by intrinsic membrane-bound CK I in erythrocytes showed marked stimulation in activities of casein kinases in the presence of A beta 1-40 or blocked A beta. We propose that A beta, by stimulating casein kinases, may contribute to abnormal protein phosphorylation in AD, in particular to increased phosphorylation of microtubule-associated proteins, leading to the neurofibrillary tangles formation and neurodegeneration in this disease. Interaction of A beta with protein kinases, thus, may characterize the beginning of the disease.
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Affiliation(s)
- A Chauhan
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314-6399
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26
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Moussavi RS, Kelley CA, Adelstein RS. Phosphorylation of vertebrate nonmuscle and smooth muscle myosin heavy chains and light chains. Mol Cell Biochem 1993; 127-128:219-27. [PMID: 7935353 DOI: 10.1007/bf01076773] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In this article we review the various amino acids present in vertebrate nonmuscle and smooth muscle myosin that can undergo phosphorylation. The sites for phosphorylation in the 20 kD myosin light chain include serine-19 and threonine-18 which are substrates for myosin light chain kinase and serine-1 and/or -2 and threonine-9 which are substrates for protein kinase C. The sites in vertebrate smooth muscle and nonmuscle myosin heavy chains that can be phosphorylated by protein kinase C and casein kinase II are also summarized. Original data indicating that treatment of human T-lymphocytes (Jurkat cell line) with phorbol 12-myristate 13-acetate results in phosphorylation of both the 20 kD myosin light chain as well as the 200 kD myosin heavy chain is presented. We identified the amino acids phosphorylated in the human T-lymphocytes myosin light chains as serine-1 or serine-2 and in the myosin heavy chains as serine-1917 by 1-dimensional isoelectric focusing of tryptic phosphopeptides. Untreated T-lymphocytes contain phosphate in the serine-19 residue of the myosin light chain, and in a residue tentatively identified as serine-1944 in the myosin heavy chain.
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Affiliation(s)
- R S Moussavi
- Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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27
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Kimura A, Nakashima S, Uda T, Ikeda H, Yasuda S, Tsuji T, Matsumura S. Heavy-chain isoforms of non-muscle myosin in human tissues. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 213:5-10. [PMID: 8477722 DOI: 10.1111/j.1432-1033.1993.tb17728.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The heavy-chain isoforms of myosin in human non-muscle and smooth muscle tissues were analyzed by means of SDS/PAGE and using three distinct newly developed monoclonal anti-(human cerebrum myosin) Ig (HBM-1, HBM-3 and HBM-4). Purified cerebrum myosin contained three electrophoretic variants of non-muscle myosin heavy chain (NM1, NM2 and NM3, with apparent molecular masses of about 200, 198 and 196 kDa, respectively). Both NM1 and NM2 were recognizable by the brain-specific antibody HBM-1, while NM3 was recognizable by HBM-3. Each of the variants reacted with HBM-4 to a similar extent. Purified cerebellum myosin gave three electrophoretic variants of the heavy chain which were indistinguishable electrophoretically or immunologically from those of cerebrum myosin. Aortic myosin contained four electrophoretic variants, including the two smooth muscle myosin heavy chain isoforms and NM2-like and NM3-like heavy chains. Liver, platelet and kidney myosins contained a heavy chain very similar to NM3. Kidney myosin also contained a small fraction of an NM2-like electrophoretic variant. In addition, cerebrum, kidney, liver and platelet myosins appeared to contain minor, 194-kDa myosin heavy-chain-like polypeptide(s) (NM4). NM1, as well as NM2 and NM3, thus appear to be the brain-type and non-brain-type non-muscle myosin heavy-chain isoforms, respectively, and additional minor heavy-chain isoforms are also likely to be present in human tissues.
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Affiliation(s)
- A Kimura
- Department of Legal Medicine, Wakayama Medical College, Japan
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28
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Takahashi M, Kawamoto S, Adelstein R. Evidence for inserted sequences in the head region of nonmuscle myosin specific to the nervous system. Cloning of the cDNA encoding the myosin heavy chain-B isoform of vertebrate nonmuscle myosin. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)37123-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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29
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Salvucci ME, Chavan AJ, Haley BE. Identification of peptides from the adenine binding domains of ATP and AMP in adenylate kinase: isolation of photoaffinity-labeled peptides by metal chelate chromatography. Biochemistry 1992; 31:4479-87. [PMID: 1581304 DOI: 10.1021/bi00133a014] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Photoaffinity labeling with azidoadenine nucleotides was used to identify peptides from the ATP and AMP binding domains on chicken muscle adenylate kinase. Competition binding studies and enzyme assays showed that the 8-azido analogues of Ap4A and ATP modified only the MgATP2- site of adenylate kinase, whereas the 2-azido analogue of ADP modified the enzyme at both the ATP and AMP sites. The positions of the two nucleotide binding sites on the enzyme were deduced by isolating and sequencing the modified peptides. Photolabeled peptides were isolated by a new procedure that used metal chelate chromatography to affinity purify the photolabeled peptides prior to final purification by reverse-phase HPLC. The sequences of the peptides that were photolabeled with the 8-azido analogues corresponded to residues K28-L44, T153-K166, and T125-E135 of the chicken muscle enzyme. The residues that were present in both tryptic- and Staphylococcus aureus V-8 protease-generated versions of these peptides were assigned to the ATP binding domain on the basis of selective photoaffinity labeling with the 8-azidoadenine analogues. These peptides and an additional peptide corresponding to positions I110-K123 were photolabeled with 2-N3ADP. Since I110-K123 was photolabeled by 2-N3ADP but not by 8-N3Ap4A, it was assigned to the AMP binding domain.
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Affiliation(s)
- M E Salvucci
- United States Department of Agriculture, University of Kentucky, Lexington
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30
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Sun W, Chantler PD. Cloning of the cDNA encoding a neuronal myosin heavy chain from mammalian brain and its differential expression within the central nervous system. J Mol Biol 1992; 224:1185-93. [PMID: 1569576 DOI: 10.1016/0022-2836(92)90482-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The complete amino acid sequence of a neuronal myosin heavy chain (MHC) from mammalian brain (1999 amino acids, 230 kDa) has been deduced by sequencing cDNA clones isolated from a rat brain cDNA library. The library was screened using an affinity-purified polyclonal antibody that had been raised against myosin purified from a neuronally-derived cell line (Neuro-2A). Restriction digests of genomic DNA from Neuro-2A cells and rat brain are consistent with an identity of the sequenced isoform from these two sources. RNA blot analysis demonstrates this myosin to exhibit differential expression within the cerebral cortex and spinal cord. No expression was observed in liver, kidney, heart, spleen or skeletal muscle, or even within other regions of the brain. The sequence of this neuronal MHC is compared with those of other non-muscle MHCs, to which it shows an overall similarity of structure, especially with respect to conserved regions within the head (ATP binding site, actin binding site, reactive thiols) and the presence of an alpha-helical coiled-coil tail that can be arranged as 28-residue repeating units plus four skip residues. A unique non-helical tailpiece composed of 72 amino acid residues marks the C-terminus of this neuronal myosin isoform.
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Affiliation(s)
- W Sun
- Department of Anatomy and Neurobiology, Medical College of Pennsylvania, Philadelphia 19129
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31
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Murakami N, Elzinga M. Immunohistochemical studies on the distribution of cellular myosin II isoforms in brain and aorta. CELL MOTILITY AND THE CYTOSKELETON 1992; 22:281-95. [PMID: 1387589 DOI: 10.1002/cm.970220408] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The distribution of nonmuscle myosin isoforms in brain and aorta was studied by using polyclonal antibodies against two synthetic peptides selected from a region near the carboxyl terminus of bovine brain (peptide IIB) and human macrophage (peptide IIA) myosin. Immunoblots of brain homogenates and purified myosin showed two major bands stained by anti-peptide IIB (MIIB1 and MIIB2) and a minor band stained by anti-peptide IIA (MIIA2). Polyclonal anti-human platelet myosin antibodies did not react with MIIB isoforms. In cryosections from bovine, rat, and mouse brains, anti-peptide IIB stained most neuronal cells. In bovine cryosections, glial staining was also observed. In contrast, anti-peptide IIA and anti-platelet myosin antibodies primarily stained blood vessels. In bovine aorta, the anti-peptide antibodies recognized four bands, MIIB3, MIIB4, MIIA1, and MIIA2. Only MIIA2 was recognized by anti-human platelet myosin antibodies. In bovine aorta cryosections, anti-peptide IIB stained smooth muscle cells in tunica intima and tunica media but did not stain endothelial cells. Anti-peptide IIA stained smooth muscle cells in the tunica media, and endothelial cells of vaso vasorum but not of aorta. Only polyclonal anti-platelet myosin antibodies stained the endothelial cells of aorta tunica intima. These results indicate that multiple isoforms of cellular myosins exist in mammals, that these isoforms are expressed in a cell specific manner, and that the major myosin isoforms isolated from whole brain originate from neurons and, at least in bovine brain, from glia, but not from blood vessels.
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Affiliation(s)
- N Murakami
- Laboratory of Neurobiochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314
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Kimura A, Tsuji T, Matoba R, Fujitani N, Ohmori K, Matsumura S. Tissue-specific and non-tissue-specific heavy-chain isoforms of myosin in the brain as revealed by monoclonal antibodies. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1118:59-69. [PMID: 1722423 DOI: 10.1016/0167-4838(91)90441-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Four types of monoclonal antibody (BM-1, BM-2, BM-3 and BM-4) each having distinctive tissue specificity were obtained by immunizing mice with purified bovine cerebrum myosin. Both BM-1 and BM-2 reacted most efficiently with cerebrum myosin and less efficiently with myosins from other limited nonmuscle tissues, the tissue specificity of BM-1 being much narrower than that of BM-2. BM-3 reacted more efficiently with several other nonmuscle myosins than with cerebellar or cerebral myosin. BM-4 recognized various nonmuscle and smooth muscle myosins with a nearly equal efficiency. Cerebral myosin as well a cerebellar myosin contained two or more electrophoretic variants of the heavy chains. BM-1 and BM-3 as well as BM-2 and BM-3 were found to recognize selectively these distinct heavy-chain isoforms. The antigenic sites of the three tissue-specific antibodies (BM-1, BM-2 and BM-3) were all localized near the head/tail junction of the myosin molecules, while that of non-tissue-specific antibody BM-4 was near the center of the tail. These and additional results indicate that mammalian brain tissues as well as several other nonmuscle tissues contain multiple heavy-chain isoforms of myosin, the levels of which differed considerably from one tissue to another.
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Affiliation(s)
- A Kimura
- Department of Legal Medicine, Wakayama Medical College, Japan
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33
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Garabedian TE, Yount RG. Direct photoaffinity labeling of gizzard myosin with vanadate-trapped adenosine diphosphate. Biochemistry 1991; 30:10126-32. [PMID: 1931944 DOI: 10.1021/bi00106a008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The active-site topology of smooth muscle myosin has been investigated by direct photoaffinity-labeling studies with [3H]ADP. Addition of vanadate (Vi) and Co2+ enabled [3H]ADP to be stably trapped at the active site (t1/2 greater than 5 days at 0 degrees C). The extraordinary stability of the myosin.Co2+.[3H]ADP.Vi complex allowed it to be purified free of excess [3H]ADP before irradiation began and ensured that only active-site residues became labeled. Following UV irradiation, approximately 10% of the trapped [3H]ADP became covalently attached at the active site. All of the [3H]ADP incorporated into the 200-kDa heavy chain, confirming earlier results using untrapped [alpha-32P]ATP [Maruta, H., & Korn, E. (1981) J. Biol. Chem. 256, 499-502]. After extensive trypsin digestion of labeled subfragment 1, HPLC separation methods combined with alkaline phosphatase treatment allowed two labeled peptides to be isolated. Sequence analysis of both labeled peptides indicated that Glu-185 was the labeled residue. Since Glu-185 has been previously identified as a residue at the active site of smooth myosin using [3H]UDP as a photolabel [Garabedian, T. E., & Yount, R. G. (1990) J. Biol. Chem. 265, 22547-22553], these results provide further evidence that Glu-185, located immediately adjacent to the glycine-rich loop, is located in the purine binding pocket of the active site of smooth muscle myosin.
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Affiliation(s)
- T E Garabedian
- Department of Biochemistry and Biophysics, Washington State University, Pullman 99164-4660
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34
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Witcher D, Kovacs R, Schulman H, Cefali D, Jones L. Unique phosphorylation site on the cardiac ryanodine receptor regulates calcium channel activity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99140-4] [Citation(s) in RCA: 146] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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Sun WD, Chantler PD. A unique cellular myosin II exhibiting differential expression in the cerebral cortex. Biochem Biophys Res Commun 1991; 175:244-9. [PMID: 1998509 DOI: 10.1016/s0006-291x(05)81226-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Clones possessing inserts of brain myosin II have been obtained by screening a rat brain cDNA expression library with a polyclonal antibody, raised against myosin II from the mouse neuroblastoma cell line, Neuro-2A. A partial sequence comprising the 3' coding and non-coding regions of the myosin message has been determined which is markedly different from other myosin sequences. The derived amino-acid sequence comprises the C-terminal 90 amino acids: VSS(PO4)LKNKLRRGDLPFVVTRRLVRKGTLELS(PO4)DDDDESKASLINETQPPQCLDQQ LDQQ LDQLFNWPVNAGCVCGWGVEQTQGEEAVHKCRT(CO2H). This sequence encompasses regions homologous to both the casein kinase II and protein kinase C heavy-chain phosphorylation sites. The non-helical "tail-piece" is considerably longer (an additional 39 amino acid residues) than found in other myosins. Northern blot analysis demonstrates this myosin II message to be unique to cerebral cortex, with no expression in all other non-cortical brain regions and peripheral tissues tested. Our results suggest functional diversity for myosin II isozymes within the brain.
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Affiliation(s)
- W D Sun
- Department of Anatomy and Neurobiology, Medical College of Pennsylvania, Philadelphia 19129
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36
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cDNA cloning of a myosin heavy chain isoform in embryonic smooth muscle and its expression during vascular development and in arteriosclerosis. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67861-0] [Citation(s) in RCA: 220] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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37
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Affiliation(s)
- J R Sellers
- Laboratory of Molecular Cardiology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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Murakami N, Mehta P, Elzinga M. Studies on the distribution of cellular myosin with antibodies to isoform-specific synthetic peptides. FEBS Lett 1991; 278:23-5. [PMID: 1993471 DOI: 10.1016/0014-5793(91)80074-d] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Antisera were produced against two synthetic peptides having sequences specific for cellular myosin heavy chains from human macrophages (peptide IIA) and bovine brain (peptide IIB). Immunoblots of tissue extracts were made with these antibodies, and they showed that mammalian cells have at least three distinct cellular myosin heavy chain isoforms. Two of the isoforms (MIIB1 and MIIB2) were recognized by antibodies against the peptide IIB, and the other (MIIA) by the anti-peptide IIA antibodies. Polyclonal anti-platelet myosin antibodies recognized the MIIA isoform, but did not recognize MIIB1 or MIIB2. The isoforms were expressed in a tissue-specific pattern; the MIIB1 isoform was found only in brain.
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Affiliation(s)
- N Murakami
- Laboratory of Neurobiochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314-6399
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Purification and characterization of a brain-specific protein kinase C substrate, neurogranin (p17). Identification of a consensus amino acid sequence between neurogranin and neuromodulin (GAP43) that corresponds to the protein kinase C phosphorylation site and the calmodulin-binding domain. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52425-x] [Citation(s) in RCA: 222] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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40
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Pearson RB, Kemp BE. Protein kinase phosphorylation site sequences and consensus specificity motifs: tabulations. Methods Enzymol 1991; 200:62-81. [PMID: 1956339 DOI: 10.1016/0076-6879(91)00127-i] [Citation(s) in RCA: 843] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Abstract
Synthetic peptide substrates for CKII are useful reagents in the analysis of phosphorylation sites when used in conjunction with biochemical and genetic analysis of the protein substrates for the enzyme. A multidisciplinary approach should be applied to the characterization of the synthetic peptide products, including amino acid analysis, sequencing, and mass spectrometry. Synthetic procedures for CKII substrate peptides often result in anisole adducts and dehydrated forms. Mass spectrometry is invaluable in identifying these contaminants, and preparative HPLC can be used to separate them from the desired product. Quantitative analysis of the CKII phosphorylation of peptides can utilize phosphocellulose paper if the peptide has a basic sequence, or thin-layer chromatography, if the peptide has no basic portion. Qualitative analysis using electrophoresis and mass spectrometry help to establish the stoichiometry of phosphorylation. Sequence analysis of phosphoserine after beta elimination and derivatization is useful in quantifying adjacent phosphorylation sites. Overall, application of a variety of techniques permits detailed analysis of CKII phosphorylation sites on synthetic peptides that are model substrates.
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Garabedian TE, Yount RG. Direct photoaffinity labeling of gizzard myosin with [3H]uridine diphosphate places Glu185 of the heavy chain at the active site. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)45740-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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43
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Jiao JA, Chollet R. Regulatory phosphorylation of serine-15 in maize phosphoenolpyruvate carboxylase by a C4-leaf protein-serine kinase. Arch Biochem Biophys 1990; 283:300-5. [PMID: 2148863 DOI: 10.1016/0003-9861(90)90646-g] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have recently reported that the light-induced changes in the enzymatic and regulatory properties of maize leaf phosphoenolpyruvate carboxylase are attributed to the regulatory seryl phosphorylation of this C4-photosynthesis enzyme. In the present study, the darkform target enzyme was phosphorylated/activated in vitro by a maize leaf protein-serine kinase, and the 32P-labeled regulatory site phosphopeptide was purified from a tryptic digest by metal-ion affinity and reversed-phase chromatography. Automated Edman degradation analysis by covalent protein sequencing technology revealed that the amino acid sequence of this phosphoseryl peptide is His-His-Ser(P)-Ile-Asp-Ala-Gln-Leu-Arg. This nonapeptide, which corresponds exactly to residues 13-21 in the deduced primary sequence of the maize leaf carboxylase, is far removed from recently identified active-site cysteine (Cys-553) and lysine (Lys-606) residues in the C-terminal region of the primary structure. Comparative analysis of the deduced N-terminal sequences of C3-, C4-, and Crassulacean acid metabolism (CAM)-leaf phosphoenolpyruvate carboxylases suggests that the motif of Lys/Arg-X-X-Ser is an important structural requirement of the C4- and CAM-leaf protein-serine kinases.
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Affiliation(s)
- J A Jiao
- Department of Biochemistry, University of Nebraska-Lincoln 68583-0718
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The 204-kDa smooth muscle myosin heavy chain is phosphorylated in intact cells by casein kinase II on a serine near the carboxyl terminus. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)38245-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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45
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Ikeda N, Yasuda S, Muguruma M, Matsumura S. Protein kinase C phosphorylates both the light chains and the head portion of the heavy chains of brain myosin. Biochem Biophys Res Commun 1990; 169:1191-7. [PMID: 2363720 DOI: 10.1016/0006-291x(90)92022-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Protein kinase C phosphorylated both the 19/21-kDa regulatory light chains and heavy chains of bovine brain myosin. The major phosphorylation sites of the light chains were on their threonyl residues, while those for myosin light chain kinase were on their seryl residues. Whereas several non-muscle regular myosins have been reported to be phosphorylated by different types of protein kinases at the non-helical small segments at the tail ends of the heavy chains, the phosphorylation sites for protein kinase C were localized on the head portion of the heavy chains of brain myosin. The possible role of phosphorylation of brain myosin by protein kinase C in the regulation of motility of neural cells is discussed.
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Affiliation(s)
- N Ikeda
- Department of Biochemistry, Saga Medical School, Japan
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