Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Henderson, Louis E.; Krutzsch, Henry C.; Oroszlan, Stephen

doi:10.1073/pnas.80.2.339

Cited by 234 publications

(144 citation statements)

References 24 publications

(19 reference statements)

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“…The Gag sequence contains a myristylation signal that is crucial for plasma membrane localization (Henderson et al, 1983). To evaluate the importance of this motif for GagBtk mediated transformation, the critical Gly residue at position two of GagBtk (Henderson et al, 1983) was mutated to Ala. The subcellular localization, transformation activity, and tyrosine phosphorylation of this myristylation defective mutant, GagMyr(7)Btk, and GagBtk were compared.…”

Section: Activation Of Gagbtk Requires the Myristylation Signalmentioning

confidence: 99%

Constitutive membrane association potentiates activation of Bruton tyrosine kinase

Rawlings

Park

et al. 1997

Oncogene

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Mutations in the nonreceptor tyrosine kinase Btk result in the B cell immunode®ciencies X-linked agammaglobulinemia (XLA) in humans and X-linked immunode®-ciency (xid) in mice. Genetic and biochemical evidence implicates Btk as a key component of several B cell signaling pathways. Activation of Btk by a point mutation (E41K) within the PH domain (Btk*) results in ®broblast transformation and is correlated with increased membrane localization of Btk. When wild type Btk is activated by coexpression with Lyn, the tyrosine phosphorylated pool of Btk is highly enriched in the membrane fraction. To determine whether membrane association is su cient to activate Btk, we targeted Btk to the plasma membrane using a series of fusion proteins including GagBtk, CD16Btk and CD4Btk. Constitutive membrane association greatly enhanced the ability of Btk to transform Rat2 ®broblasts in the presence of high levels of Src activity. All membrane targeted forms of Btk were highly tyrosine phosphorylated. Transformation required membrane localization, Btk kinase activity, transphosphorylation by Src family kinases, and an intact SH2 domain but not the PH or SH3 domains. These data suggest that membrane localization is a critical early step in Btk activation.

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Section: Activation Of Gagbtk Requires the Myristylation Signalmentioning

confidence: 99%

Constitutive membrane association potentiates activation of Bruton tyrosine kinase

Rawlings

Park

et al. 1997

Oncogene

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“…Both proteins possess the N-terminal sequence myristyl-Gly-Asn-. Recently three protein tyrosine kinases have been shown to contain this CI4-saturated fatty acid at their N-termini, namely the transforming gene products of Rous sarcoma virus [40] and murine leukaemia virus [41], and a protein kinase in the transformed T-cell line LSTRA [42]. The role of this unusual N-terminal modification is unclear.…”

Section: Protein Piiosphatuse-2b ( P P -2 B ) a Ca2+ -Dependent Culmentioning

confidence: 99%

The role of protein phosphorylation in the hormonal control of enzyme activity

1985

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A major goal of molecular pharmacology is to account for the extreme biological potency and great diversity of action of hormones. These extracellular signals circulate in the blood at nanomolar or subnanomolar concentrations, and yet within seconds they can produce millimolar changes in the levels of metabolites. Hormonal stimuli must therefore be amplified a million-fold or more following their interaction with plasma-membrane-bound rcceptors. Furthermore, the actions of a hormone are nearly always pleiotropic, affecting many processes within a givcn target cell, and eliciting quite distinct responses in diffcrent cell types.Amplification and diversity in hormone action are achieved by two principal mechanisms, namely the reversible phosphorylation of proteins ( Fig. 1) and the formation of molecular species termed 'second messengers'. Many key regulatory proteins exist in either a phosphorylated or a dephosphorylated form, their steady-state levels of phosphorylation reflecting the relative activities of the protein kinases and phosphatases that catalyse the interconversion process. Phosphorylation of seryl, threonyl, or occasionally tyrosyl residues, trigger small conformational changes in these proteins, which alter their biological properties. Hormones transmit information to the interior of the cell by activating transmembrane signalling systems that control production of a relatively small number of chemical mediators or second messengers. These substances regulate protein kinase and phosphatase activities, and so alter the phosphorylation states of many intracellular proteins, explaining the diversity of action of hormones [I, 21.Amplification of hormonal stimuli is achieved at several levels. Firstly, second messengers are formed in micromolar concentrations in response to nanomolar levels of hormones.Secondly, each molecule of protein kinase (or phosphatase) may catalyse the phosphorylation (or dephosphorylation) of many molecules of regulatory protein. Thirdly, in the case of regulatory proteins that are enzymes, each molecule of enzyme may catalyse the transformation of many molecules of substrate to product.In this lecture I will review the role of protein phosphorylation and dephosphorylation in the regulation of cellular activity, with emphasis on the hormonal control of metabolic pathways where the intracellular targets for phosphorylation are enzymes. However, while these systems are the best understood in molecular terms, it should be emphasized that phosphorylation also modifies the functions of proteins that are not enzymes and that almost all cellular processes are controlled by this versatile post-translational modification. Cyclic-A M P-dependcw t protein kinuseA large number of hormones exert their effects by increasing or decreasing the concentration of cyclic AMP, and the transmcmbrane signalling systems involved in the formation of this second messenger are starting to be understood in molecular detail [3]. The effects of cyclic AMP on metabolic pathways are mediated by cyclic-AMP-dep...

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“…Even when [3H]palmitic acid is used to label p6Osrc, all of the inefficient labeling which is observed (39; Buss and Sefton, in press) reflects incorporation of [3H]myristic acid arising from metabolism of the [3H]palmitic acid (Buss and Sefton, in press). Furthermore, where chemical analysis has been possible, all of the fatty acid in the catalytic subunit, p15rag, and calcineurin has been found to be myristic acid (1,6,15).…”

mentioning

confidence: 99%

“…These are the cellular and viral forms of p6Osrc (Buss and Sefton, in press), the catalytic subunit of the cyclic AMP-dependent protein kinase (6), the protein phosphatase, calcineurin B (1), the T-cell-specific p56 protein from LSTRA cells (41), and proteins which contain the p15rag protein of mammalian retroviruses (15,35). This last group includes the unglycosylated forms of a number of gag-onc fusion proteins such as Abelson murine leukemia virus P120gag-abl and Snyder-Theilen feline sarcoma virus P85gag-fes (34).…”

mentioning

confidence: 99%

Myristic acid is attached to the transforming protein of Rous sarcoma virus during or immediately after synthesis and is present in both soluble and membrane-bound forms of the protein.

Buss¹,

Kamps²,

Sefton³

1984

Mol. Cell. Biol.

183

149

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Myristic acid, a minor component of cellular fatty acids, has been shown previously to be covalently bound to most molecules of p60, the transforming protein of Rous sarcoma virus. We have now determined at what time during the life cycle of p6Osrc, and where within the cell, this lipid becomes attached to the protein. p6Osrc was found to acquire myristic acid at only one time, during or immediately after its synthesis. p6OSc is known to be synthesized on free polysomes and appears at the cytoplasmic face of the plasma membrane after a lag of 10 min. The addition of myristic acid to p6ps therefore precedes the binding of the protein to the plasma membrane. The lipid attached to p60sr is a permanent, metabolically stable part of the protein; we found no evidence for turnover of the myristyl moiety. However, we did find myristate attached to various soluble forms of p60src and to a large number of cytosolic cellular proteins as well. This demonstrates that the attachment of myristic acid to a protein is not in itself sufficient to convert a soluble protein into a membrane-bound protein.p6 src, the transforming protein of Rous sarcoma virus (RSV) (5) is a protein kinase which phosphorylates tyrosine residues in substrate proteins (7,16,22). p60src undergoes an unusual form of protein modification: the 14-carbon saturated fatty acid, myristic acid, is covalently attached to its amino terminus (39; J. E. Buss and B. M. Sefton, J. Virol., in press). In these studies we have characterized the time and intracellular location of myristic acid addition to p6OSrc and analyzed the effect of temperature-sensitive mutations on this process.Although few studies have examined the biochemistry of fatty acylation of proteins, two different types of modification are known to occur. The 16-carbon saturated fatty acid, palmitic acid, has been shown to be present in a variety of membrane-associated proteins. These include the transferrin receptor (24); p2lras, the transforming protein of Harvey murine sarcoma virus (39); and the El and E2 glycoproteins of Sindbis virus and the G glycoprotein of vesicular stomatitis virus (31, 32). The palmityl group is attached to these proteins via ester bonds to cysteine (30) or possibly serine residues (32). The addition of ester-linked palmitate is clearly a posttranslational event. The fatty acid is added to viral glycoproteins in the Golgi apparatus ca. 20 min after their synthesis (33), and only the mature forms of p2lras and the transferrin receptor contain palmitic acid (25, 39).Only five identified proteins are known to contain a covalently attached myristic acid. These are the cellular and viral forms of p6Osrc (Buss and Sefton, in press), the catalytic subunit of the cyclic AMP-dependent protein kinase (6), the protein phosphatase, calcineurin B (1), the T-cell-specific p56 protein from LSTRA cells (41), and proteins which contain the p15rag protein of mammalian retroviruses (15,35). This last group includes the unglycosylated forms of a number of gag-onc fusion proteins such as Abelson m...

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Myristyl amino-terminal acylation of murine retrovirus proteins: An unusual post-translational protein modification

Cited by 234 publications

References 24 publications

Constitutive membrane association potentiates activation of Bruton tyrosine kinase

Constitutive membrane association potentiates activation of Bruton tyrosine kinase

The role of protein phosphorylation in the hormonal control of enzyme activity

Myristic acid is attached to the transforming protein of Rous sarcoma virus during or immediately after synthesis and is present in both soluble and membrane-bound forms of the protein.

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