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001-es BibID:	BIBFORM028870
Első szerző:	Hartshorne, David J.
Cím:	Myosin light chain phosphatase : subunit composition, interactions and regulation / David J. Hartshorne, Masaaki Ito, Ferenc Erdődi
Dátum:	1998
ISSN:	0142-4319
Megjegyzések:	This review has presented some of the recent data on myosin phosphatase from smooth muscle. Although it is not conclusive, it is likely that most of the myosin phosphatase activity is represented by a holoenzyme composed of three subunits. These are: a catalytic subunit of 38 kDa of the type 1 phosphatase, probably the delta isoform (i.e. PP1c delta); a subunit of about 20 kDa whose function is not established; and a larger subunit that is thought to act as a target subunit. This is termed the myosin phosphatase target subunit, MYPT. Various isoforms of MYPT exist and the relatively minor distinctions are in the C-terminal leucine zipper motifs and/or with inserts in the central region. Many regions of the molecule are highly conserved, including the ankyrin repeats in the N-terminal part of the molecule and the sequence around the phosphorylation site. In addition, these isoforms all contain the four residue PP1c-binding motif (Arg/Lys-Val/Ile-Xaa-Phe). MYPT has been detected in a variety of cells and thus is not unique to smooth muscle. With phosphorylated myosin as substrate, the phosphatase activity of PP1c is low and is enhanced on addition of MYPT. It is assumed that MYPT functions as a target subunit and binds to both PP1c and substrate. The N-terminal fragment of MYPT is responsible for the activation of PP1c activity, but how much of the N-terminal sequence is required is not established. An important point is that activation is not a general effect and is specific for myosin. It is not known if other substrates may be targeted to MYPT. There are two binding sites for PP1c on MYPT: a strong site in the N-terminal segment (containing the 4-residue motif) and a weaker site in the ankyrin repeats, possibly in repeats 5, 6 and 7. The location(s) of the myosin-binding sites on MYPT is controversial, and binding of myosin, or light chain, to both N- and C-terminal fragments has been reported. Regulation of myosin phosphatase activity involves changes in subunit interactions, although molecular mechanisms are not defined. There are basically two theories proposed for phosphatase inhibition (i.e. as seen in the agonist-induced increase in Ca2+ sensitivity). One hypothesis is that phosphorylation of Myosin light chain phosphatase MYPT (at residue 654 or 695 of the gizzard MYPT isoforms or an equivalent residue) inhibits the activity of the MP holoenzyme. The kinase involved is not established, but may be an unidentified endogenous kinase or a RhoA-activated kinase. The latter is an attractive possibility because there is convincing evidence that RhoA plays a crucial role in the Ca(2+)-sensitizing process in smooth muscle. A second idea involves arachidonic acid. This is released via phospholipase A2 and could either interact directly with MYPT and cause dissociation of the holoenzyme (thus effectively reducing the phosphatase activity to that of the isolated catalytic subunit), or it could activate a kinase that would phosphorylate MYPT and inhibit the phosphatase. It is possible that MP activity may also be activated, for example, following increases in cAMP and/or cGMP. Evidence in support of this is very limited and under in vivo conditions the phosphorylation of MYPT by the respective kinases has not been demonstrated. There is, however, a tentative hypothesis based on in vitro data that phosphorylation of MYPT by PKA alters its cellular localization. This involves a shuttle between the dephosphorylated membrane-bound and inhibited state (at least towards P-myosin) to a phosphorylated cytosolic or cytoskeletal, and active state. The pathway(s) discussed above originates at the cell membrane and is carried via one or more messengers to the level of the contractile apparatus where it is manifested by regulation of phosphatase activity. Various components of the route have been identified, including RhoA and the atypical PKC isoforms, but more remain to be discovered. It is possible that more than one pathway, or cascade, is
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Muscle Research And Cell Motility. - 19 : 4 (1998), p. 325-341. -
További szerzők:	Ito, Masaaki Erdődi Ferenc (1953-) (biokémikus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM064059
Első szerző:	Sipos Adrienn (biológus, biotechnológus)
Cím:	Myosin phosphatase regulates gene expression via mediating arginine methylation in human hepatocarcinoma cells / Adrienn Sipos, Dániel Horváth, Zsuzsanna Darula, Ferenc Erdődi, Beáta Lontay
Dátum:	2013
ISSN:	0142-4319
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idézhető absztrakt
Megjelenés:	Journal Of Muscle Research And Cell Motility. - 35 : 3-4 (2013), p. 244. -
További szerzők:	Horváth Dániel (1989-) (molekuláris biológus) Darula Zsuzsanna Erdődi Ferenc (1953-) (biokémikus) Lontay Beáta (1975-) (biokémikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM028723
Első szerző:	Wu, Yue
Cím:	Myosin phosphatase and myosin phosphorylation in differentiating C2C12 cells / Yue Wu, Ferenc Erdődi, Andrea Murányi, Kevin D. Nullmeyer, Ronald M. Lynch, David J. Hartshorne
Dátum:	2003
ISSN:	0142-4319
Megjegyzések:	C2C12 cells offer a useful model to study the differentiation of non-muscle cells to skeletal muscle cells. Myosin phosphorylation and changes in related enzymes, with an emphasis on myosin phosphatase (MP) were analyzed over the first 6 days of C2C12 differentiation. There was a transition from myosin phosphatase target subunit 1 (MYPT1), predominant in the non-muscle cells to increased expression of MYPT2. Levels of MYPT1/2 were estimated, and both isoforms were higher in non- or partially differentiated cells compared to the concentrations in the differentiated isolated myotubes from day 6. A similar profile of expression was estimated for the type 1 protein phosphatase catalytic subunit, delta isoform (PP1c delta). Phosphatase activities, using phosphorylated smooth and skeletal muscle myosins, were estimated for total cell lysates and isolated myotubes. In general, smooth muscle myosin was the preferred substrate. Although the expression of MYPT1/2 and PP1c delta was considerably reduced in isolated myotubes the phosphatase activities were not reduced to corresponding levels. Most of the MP activity was due to PP1c, as indicated by okadaic acid. In spite of relatively high expression of MYPT1/2 and PP1c delta, marked phosphorylation of non-muscle myosin (over 50% of total myosin) was observed at day 2 (onset of expression of muscle-specific proteins) and both mono- and diphosphorylated light chains were observed. Partial inhibition of MLCK by 1-(5-chloronaphthalene-1-sulphonyl)-1H-hexahydro-1,4-diazepine HCl (ML-9) or by a construct designed from the autoinhibitory domain of MLCK, resulted in an increase in small myotubes (3-5 nuclei) after 3 days of differentiation and a decrease in larger myotubes (compared to control). The effect of ML-9 was not due to a reduction in intracellular Ca2+ levels. These results suggest that phosphorylation of non-muscle myosin is important in growth of myotubes, either in the fusion process to form larger myotubes or indirectly, by its role in sarcomere organization.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Muscle Research and Cell Motility. - 24 : 8 (2003), p. 499-511. -
További szerzők:	Murányi Andrea (1966-) (biokémikus) Nullmeyer, Kevin D. Lynch, Ronald M. Hartshorne, David J. Erdődi Ferenc (1953-) (biokémikus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM003572
Első szerző:	Wu, Yue
Cím:	Localization of myosin phosphatase target subunit and its mutants / Wu Y., Murányi A., Erdődi F., Hartshorne D. J.
Dátum:	2005
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban smooth muscle MYPT nuclear localization transient transfection
Megjelenés:	Journal of Muscle Research and Cell Motility. - 26 : 2-3 (2005), p. 123-134. -
További szerzők:	Murányi Andrea (1966-) (biokémikus) Hartshorne, David J. Erdődi Ferenc (1953-) (biokémikus)
Internet cím:	elektronikus változat
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