Zeugmatin is Part of the Z-band Targeting Region of Titin.

Turnacioglu, Kenan K.; Mittal, Balraj; Dabiri, Guissou A.; Sanger, Jean M.; Sanger, Joseph W.

doi:10.1247/csf.22.73

Cited by 42 publications

(48 citation statements)

References 33 publications

(3 reference statements)

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“…3). Transfections of muscle cells with plasmids coding for GFP alone did not lead to any specific localization of GFP fluorescence (9).…”

Section: Resultsmentioning

confidence: 85%

“…1). During the transition from premyofibril to myofibril, it is postulated that there is an exchange of nonmuscle myosin IIB filaments for muscle myosin II filaments and a growth and fusion of Z-bodies into Z-bands (1,2). The Z-bodies appear initially as discrete aggregates of ␣-actinin along the premyofibrils.…”

mentioning

confidence: 99%

“…The development of plasmids coding for green fluorescent protein (GFP) (6) has permitted fluorescent cytoskeletal and muscle proteins to be expressed and observed in living cells for extended periods of time (7)(8)(9). We have coupled GFP to muscle ␣-actinin and transfected spreading embryonic chicken cardiomyocytes to follow myofibrillogenesis in spreading cardiomyocytes.…”

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confidence: 99%

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Myofibrillogenesis visualized in living embryonic cardiomyocytes

Dabiri

Turnacioglu

Sanger

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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220

266

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Myofibril formation was visualized in cultured live cardiomyocytes that were transfected with plasmids expressing green f luorescent protein (GFP) linked to the Z-band protein, ␣-actinin. The expression of this f luorescent protein provided an in vivo label for structures containing ␣-actinin. The GFP-␣-actinin fusion protein was incorporated into Z-bands, intercalated discs, and attachment plaques, as well as into the punctate aggregates, or Z-bodies, that are thought to be the precursors of Z-bands. Observations of live cells over several days in culture permitted us to test aspects of several theories of myofibril assembly that had been proposed previously based on the study of fixed cells. Fine fibrils, called premyofibrils, that formed de novo at the spreading edges of cardiomyocytes, contained punctate concentrations of ␣-actinin, termed Z-bodies. The punctate Zbodies grew and aligned with Z-bodies in adjacent fibrils. With increasing time, adjacent fibrils and Z-bodies appeared to fuse and form mature myofibrils and Z-bands in cytoplasmic regions where the linear arrays of Z-bodies had been. These new myofibrils became aligned with existing myofibrils at their Z-bands to form myofibrils that spanned the length of the spread cell. These results are consistent with a model that postulates that the fibrils that form de novo near the cell membrane are premyofibrils-i.e., the precursors of mature myofibrils.The formation of a myofibril involves the precise ordering of multiple subunits into a linear array of sarcomeres. One of the challenges in muscle research is to delineate the sequence of steps occurring in a cell during the assembly of the thick and thin filaments and Z-bands to form sarcomeres and myofibrils. We have recently proposed a model for the assembly of myofibrils based on antibody staining of chicken cardiomyocytes fixed at different times after spreading in culture (1). This model postulates that premyofibrils, characterized by banded patterns of ␣-actinin-rich Z-bodies and nonmuscle myosin IIB, form at the edges of spreading cardiomyocytes and develop into mature myofibrils (Fig. 1). During the transition from premyofibril to myofibril, it is postulated that there is an exchange of nonmuscle myosin IIB filaments for muscle myosin II filaments and a growth and fusion of Z-bodies into Z-bands (1, 2). The Z-bodies appear initially as discrete aggregates of ␣-actinin along the premyofibrils. As the myofibrils increase in width, the Z-bands appear to be composed of laterally aligned Z-bodies and finally continuous bands of ␣-actinin (see Fig. 1). A second model of myofibrillogenesis proposes that the first fibrils that form at the periphery of spreading cardiomyocytes are temporary scaffolds along which myofibrils assemble (3). Finally, there is a third hypothesis that spatially separate complexes of actin filaments and Z-bands, I-Z-I brushes, and groups of myosin thick filaments assemble independently of one another and become spliced together by titin filaments and then inserted at the en...

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“…3). Transfections of muscle cells with plasmids coding for GFP alone did not lead to any specific localization of GFP fluorescence (9).…”

Section: Resultsmentioning

confidence: 85%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Myofibrillogenesis visualized in living embryonic cardiomyocytes

Dabiri

Turnacioglu

Sanger

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

220

266

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“…The monoclonal antibodies against titin (anti-titin, clone 9D10, IgM), integrin ␣6 (clone P2C62C4, IgG1), integrin ␤1 (clone CSAT, IgG2b), zeugmatin (clone mab20, IgG2a, Turnacioglu et al, 1997), sarcomeric myosin (clone MF20, IgG2b), and skeletal muscle sarcoplasmic reticulum (clone 12/101, IgG1, Griffin et al, 1987) were obtained from the Developmental Studies Hybridoma Bank (Iowa). The monoclonal anti-smooth muscle ␣-actin (clone 1A4, IgG2a; Skalli et al, 1986), anti-myosin light chain (clone MY-21, IgM), anti-N-cadherin (clone CH19, IgG1), anti-␤-actin (clone AC-15, IgG1), anti-vinculin (clone VIN-11-5, IgG1), and anti-sarcomeric ␣-actinin (clone EA53, IgG1) were purchased from Sigma.…”

Section: Antibodiesmentioning

confidence: 99%

Rho kinase inhibitor Y27632 affects initial heart myofibrillogenesis in cultured chick blastoderm

Sakata

Sakabe

Matsui

et al. 2006

Developmental Dynamics

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During early vertebrate development, Rho-associated kinases (ROCKs) are involved in various developmental processes. Here, we investigated spatiotemporal expression patterns of ROCK1 protein and examined the role of ROCK during initial heart myofibrillogenesis in cultured chick blastoderm. Immunohistochemistry showed that ROCK1 protein was distributed in migrating mesendoderm cells, visceral mesoderm of the pericardial coelom (from which cardiomyocytes will later develop), and cardiomyocytes of the primitive heart tube. Pharmacological inhibition of ROCK by Y27632 did not alter the myocardial specification process in cultured posterior blastoderm. However, Y27632 disturbed the formation of striated heart myofibrils in cultured posterior blastoderm. Furthermore, Y27632 affected the formation of costamere, a vinculin/integrin-based rib-like cell adhesion site. In such cardiomyocytes, cell-cell adhesion was disrupted and N-cadherin was distributed in the perinuclear region. Pharmacological inactivation of myosin light chain kinase, a downstream of ROCK, by ML-9 perturbed the formation of striated myofibrils as well as costameres, but not cell-cell adhesion. These results suggest that ROCK plays a role in the formation of initial heart myofibrillogenesis by means of actin-myosin assembly, and focal adhesion/costamere and cell-cell adhesion. Developmental Dynamics 236:461-472, 2007.

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“…In a study of spreading cardiac myocytes (Rhee et al, 1994;Turnacioglu et al, 1997;L. Russo et al, 1997), three morphological stages were observed as myofibrils were being assembled: premyofibril, nascent myofibril, and mature myofibril stages.…”

Section: Implications For Myofibrillogenesismentioning

confidence: 99%

An N-terminal fragment of titin coupled to green fluorescent protein localizes to the Z-bands in living muscle cells: overexpression leads to myofibril disassembly.

Turnacioglu

Mittal

Dabiri

et al. 1997

MBoC

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Cultures of nonmuscle cells, skeletal myotubes, and cardiomyocytes were transfected with a fusion construct (Z1.1GFP) consisting of a 1.1-kb cDNA (Z1.1) fragment from the Z-band region of titin linked to the cDNA for green fluorescent protein (GFP). The Z1.1 cDNA encodes only 362 amino acids of the approximately 2000 amino acids that make up the Z-band region of titin; nevertheless, the Zl.lGFP fusion protein targets the a-actininrich Z-bands of contracting myofibrils in vivo. This fluorescent fusion protein also localizes in the nascent and premyofibrils at the edges of spreading cardiomyocytes. Similarly, in transfected nonmuscle cells, the Zl.lGFP fusion protein localizes to the a-actinin-containing dense bodies of the stress fibers in vivo. A dominant negative phenotype was also observed in living cells expressing high levels of this Zl.lGFP fusion protein, with myofibril disassembly occurring as titin-GFP fragments accumulated. These data indicate that the Z-band region of titin plays an important role in maintaining and organizing the structure of the myofibril. The Z1.1 cDNA was derived from a chicken cardiac Agtl 1 expression library, screened with a zeugmatin antibody. Recent work has suggested that zeugmatin is actually part of the N-terminal region of the 81-kb titin cDNA. A reverse transcriptase polymerase chain reaction using a primer from the distal end (5' end) of the Zl.1 zeugmatin cDNA and a primer from the nearest known proximal (3' end) chicken titin (also called connectin) cDNA resulted in a predicted 0.3-kb polymerase chain reaction product linking the two known chicken titin cDNAs to each other. The linking region had a 79% identity at the amino acid level to human cardiac titin. This result and a Southern blot analysis of chicken genomic DNA hybridized with Z1.1 add further support to our original suggestion that zeugmatin is a proteolytic fragment from the N-terminal region of titin. The Z-bands of striated muscles anchor the thin fila-sin filaments (titin). Nebulin, a 775-kDa protein with ments of the sarcomere and are also sites of insertion its C-terminal end embedded in the Z-band, binds for the two largest muscle proteins: nebulin and titin. along the entire 1-.m length of the thin filament (Labeit and Kolmerer, 1995b). Titin, also known as conThese proteins exist as single polypeptides that bind nectin, therest polypeptide known a monectin, iS the largest polypeptide known with a mo-

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Zeugmatin is Part of the Z-band Targeting Region of Titin.

Cited by 42 publications

References 33 publications

Myofibrillogenesis visualized in living embryonic cardiomyocytes

Myofibrillogenesis visualized in living embryonic cardiomyocytes

Rho kinase inhibitor Y27632 affects initial heart myofibrillogenesis in cultured chick blastoderm

An N-terminal fragment of titin coupled to green fluorescent protein localizes to the Z-bands in living muscle cells: overexpression leads to myofibril disassembly.

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