Scholars@Duke
Frederick Schachat

Frederick Schachat

Associate Professor Emeritus of Cell Biology
Cell Biology
f.schachat@cellbio.duke.edu
Duke Box 3011, Durham, NC 27710
466 Sands Bldg, Durham, NC 27710

Selected Publications

The troponin I: inhibitory peptide uncouples force generation and the cooperativity of contractile activation in mammalian skeletal muscle.

Journal Article J Muscle Res Cell Motil · May 2013 Hodges and his colleagues identified a 12 amino acid fragment of troponin I (TnI-ip) that inhibits Ca(2+)-activated force and reduces the effectiveness Ca(2+) as an activator. To understand the role of troponin C (TnC) in the extended cooperative interacti ... Full text Link to item Cite

The superfast extraocular myosin (MYH13) is localized to the innervation zone in both the global and orbital layers of rabbit extraocular muscle.

Journal Article J Exp Biol · October 2002 Featured Publication Extraocular muscles (EOMs) are the most molecularly heterogeneous and physiologically diverse mammalian striated muscles. They express the entire array of striated muscle myosins, including a specialized myosin heavy chain MYH13, which is restricted to ext ... Full text Link to item Cite

Phylogenetic implications of the superfast myosin in extraocular muscles.

Journal Article J Exp Biol · August 2002 Featured Publication Extraocular muscle exhibits higher-velocity and lower-tension contractions than other vertebrate striated muscles. These distinctive physiological properties are associated with the expression of a novel extraocular myosin heavy chain (MYH). Encoded by the ... Full text Link to item Cite

Longitudinal variation in muscle protein expression and contraction kinetics of largemouth bass axial muscle.

Journal Article J Exp Biol · December 2001 Featured Publication The present study investigates muscle protein expression in largemouth bass Micropterus salmoides through intra- and intermyomeric comparisons of white muscle. Using denaturing SDS-polyacrylamide gel electrophoresis, muscle protein expression in the arm an ... Full text Link to item Cite

Fluorescence changes on contractile activation in TnC(DANZ) labeled skinned rabbit psoas fibers.

Journal Article J Muscle Res Cell Motil · 2001 Featured Publication The increase in fluorescence of dansylaziridine (DANZ) labeled troponin C (TnC(DANZ) substituted into skinned rabbit psoas fibers was determined as a function of the pCa. The fluorescence data are expressed as the ratio of two wavelength bands, one that se ... Full text Link to item Cite

Differences in skeletal muscle between men and women with chronic heart failure.

Journal Article J Appl Physiol (1985) · January 2001 Featured Publication Men with chronic heart failure (CHF) have alterations in their skeletal muscle that are partially responsible for a decreased exercise tolerance. The purpose of this study was to investigate whether skeletal muscle alterations in women with CHF are similar ... Full text Link to item Cite

Early specialization of the superfast myosin in extraocular and laryngeal muscles.

Journal Article J Exp Biol · August 2000 Featured Publication Extraocular muscle (EOM) exhibits high-velocity, low-tension contractions compared with other vertebrate striated muscles. These distinctive properties have been associated with a novel myosin heavy chain (MyHC) isoform, MyHC-EO. An atypical MyHC, MyHC IIL ... Full text Link to item Cite

Isoforms of alpha-actinin from cardiac, smooth, and skeletal muscle form polar arrays of actin filaments.

Journal Article J Cell Biol · May 1, 2000 Featured Publication We have used a positively charged lipid monolayer to form two-dimensional bundles of F-actin cross-linked by alpha-actinin to investigate the relative orientation of the actin filaments within them. This method prevents growth of the bundles perpendicular ... Full text Link to item Cite

Capillary density of skeletal muscle: a contributing mechanism for exercise intolerance in class II-III chronic heart failure independent of other peripheral alterations.

Journal Article J Am Coll Cardiol · June 1999 OBJECTIVES: The study was conducted to determine if the capillary density of skeletal muscle is a potential contributor to exercise intolerance in class II-III chronic heart failure (CHF). BACKGROUND: Previous studies suggest that abnormalities in skeletal ... Full text Link to item Cite

Altered expression of myosin heavy chain in the vastus lateralis muscle in patients with COPD.

Journal Article Eur Respir J · April 1999 This study was designed to further characterize peripheral skeletal muscle alterations in patients with chronic obstructive pulmonary disease (COPD) and to evaluate the possible relationship between myosin heavy chain (MyoHC) isoform expression and exercis ... Full text Link to item Cite

Rostral-caudal variation in troponin T and parvalbumin correlates with differences in relaxation rates of cod axial muscle.

Journal Article J Exp Biol · November 1998 Relaxation rate is an important determinant of axial muscle power production during the oscillatory contractions of undulatory locomotion. Recently, significant differences have been reported in the relaxation rates of rostral versus caudal white muscle fi ... Full text Link to item Cite

Identification of troponin C antagonists from a phage-displayed random peptide library.

Journal Article J Biol Chem · September 4, 1998 Affinity purification of a phage-displayed library, expressing random peptide 12-mers at the N terminus of protein III, has identified 10 distinct novel sequences which bind troponin C specifically. The troponin C-selected peptides yield a consensus bindin ... Full text Link to item Cite

Troponin C modulates the activation of thin filaments by rigor cross-bridges.

Journal Article Biophys J · May 1997 Extraction of troponin C (TnC) from skinned muscle fibers reduces maximum Ca2+ and rigor cross-bridge (RXB)-activated tensions and reduces cooperativity between neighboring regulatory units (one troponin-tropomyosin complex and the seven associated actins) ... Full text Link to item Cite

Physiologically regulated alternative splicing patterns of fast troponin T RNA are conserved in mammals.

Journal Article Am J Physiol · January 1996 NH2-terminal isoforms of fast troponin T (TnT) are generated by alternative splicing of fast TnT RNA transcripts. Significantly different estimates for the number of isoforms have been obtained by nucleic acid and protein chemical studies. To resolve this ... Full text Link to item Cite

Chicken perinatal troponin Ts are generated by a combination of novel and phylogenetically conserved alternative splicing pathways.

Journal Article Dev Biol · September 1995 During perinatal development, avian and mammalian skeletal muscles express a novel set of troponin T (TnT) isoforms with higher M(r)s and more acidic pIs than their adult counterparts. In mammals, these TnTs result from the incorporation of a developmental ... Full text Link to item Cite

The developmental switch in ventricular myosin expression in vivo is not triggered by an increase in cyclic AMP.

Journal Article Reprod Fertil Dev · 1995 Ventricular myosin heavy chain (HC) expression undergoes a rapid change from the beta to the alpha isoform shortly after birth. Thyroid hormone is required for this transition to occur, but the time course of developmental changes in circulating thyroid ho ... Full text Link to item Cite

Calmodulin is intrinsically LESS effective than troponin C in activating skeletal muscle contraction.

Journal Article FEBS Lett · October 10, 1994 Calmodulin (CaM) and troponin C (TnC) are evolutionarily and structurally homologous, yet they are not functionally interchangeable. In particular, CaM cannot effectively substitute for TnC as an activator of skeletal muscle contraction. To determine if th ... Full text Link to item Cite

Identification of a fetal exon in the human fast troponin T gene.

Journal Article FEBS Lett · August 15, 1994 A developmentally regulated exon has been identified in the 5'-alternatively spliced region of the human fast Troponin T (TnT) gene. Expressed in fetal (but not adult) muscle, this exon is homologous with the fetal exons recently described in the rabbit an ... Full text Link to item Cite

Coordinate changes in C protein and myosin expression during skeletal muscle hypertrophy.

Journal Article Am J Physiol · August 1994 In this study, two new C protein isoforms in adult rat skeletal muscle were resolved using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These isoforms migrated between previously identified fast (Cf) and slow (Cs) C protein isoforms; hence th ... Full text Link to item Cite

Tropomyosin. Does resolution lead to reconciliation?

Journal Article Curr Biol · July 1, 1994 New electron microscopic data provide direct evidence in support of the classic steric-blocking model for regulation of actin-myosin interactions by tropomyosin. ... Full text Link to item Cite

beta Adrenergic control of c-fos protooncogene expression in developing rat brain regions.

Journal Article J Pharmacol Exp Ther · June 1994 The protooncogene c-fos encodes a nuclear protein that acts as a powerful enhancer of gene transcription, and shares the same general patterns of reactivity to stimulation as ornithine decarboxylase, an essential enzyme in cell replication and differentiat ... Link to item Cite

Origin of fetal troponin T: developmentally regulated splicing of a new exon in the fast troponin T gene.

Journal Article Dev Biol · August 1993 We have identified a new exon in the fast troponin T (TnT) gene whose alternative splicing is developmentally regulated. In previous studies three novel isoforms of TnT were identified in fetal and neonatal rabbit skeletal muscles (Briggs et al., 1990, Dev ... Full text Link to item Cite

Biochemical comparison of fast- and slow-contracting squid muscle.

Journal Article J Exp Biol · July 1992 The myofilament protein compositions of muscle fibres from the transverse muscle mass of the tentacles and the transverse muscle mass of the arms of the loliginid squid Sepioteuthis lessoniana were compared. These two muscle masses are distinct types, diff ... Full text Link to item Cite

Glucocorticoids accelerate the ontogenetic transition of cardiac ventricular myosin heavy-chain isoform expression in the rat: promotion by prenatal exposure to a low dose of dexamethasone.

Journal Article J Dev Physiol · July 1992 Cardiac myosin heavy chain expression undergoes a perinatal transition from predominance of beta-MHC to alpha-MHC. In the current study, we tested the effects of glucocorticoids in this early transition period, by treating pregnant rats with dexamethasone ... Link to item Cite

Ontogenetic transition of cardiac myosin heavy chain isoforms in rat ventricle: effects of fetal exposure to beta-adrenergic agonists or antagonists.

Journal Article J Dev Physiol · April 1992 Cardiac myosin heavy chain (MHC) expression undergoes an ontogenetic transition from beta to alpha MHC isoforms. Although thyroid hormone plays a role in this change, the timing of the events suggests the participation of other factors. Using a new, denatu ... Link to item Cite

Transitions from fetal to fast troponin T isoforms are coordinated with changes in tropomyosin and alpha-actinin isoforms in developing rabbit skeletal muscle.

Journal Article Dev Biol · August 1990 In adult fast skeletal muscle, specific combinations of thin filament and Z-line protein isoforms are coexpressed. To determine whether the expression of these sets of proteins, designated the TnT1f, TnT2f, and TnT3f programs, is coordinated during develop ... Full text Link to item Cite

Co-operative activation of skeletal muscle thin filaments by rigor crossbridges. The effect of troponin C extraction.

Journal Article J Mol Biol · April 5, 1990 When Ca2+ binds to troponin C (TnC), all 26 troponin-tropomyosin (Tn-Tm) complexes of a regulatory strand change in concert from the inactive to the active configuration. To see if the complexes respond similarly when they are activated by rigor crossbridg ... Full text Link to item Cite

N-terminal amino acid sequences of three functionally different troponin T isoforms from rabbit fast skeletal muscle.

Journal Article J Mol Biol · March 5, 1989 The different isoforms of fast skeletal muscle troponin T (TnT) are generated by alternative splicing of several 5' exons in the fast TnT gene. In rabbit skeletal muscle this process results in three major fast TnT species, TnT1f, TnT2f and TnT3f, that dif ... Full text Link to item Cite

Coordinate changes in fast thin filament and Z-line protein expression in the early response to chronic stimulation.

Journal Article J Biol Chem · October 5, 1988 The early response to chronic low frequency stimulation is characterized by coordinate changes in fast thin filament and Z-line protein expression prior to the expression of slow contractile proteins. Within the first 3 weeks of intervention there is 1) a ... Link to item Cite

Expression of a novel combination of fast and slow troponin T isoforms in rabbit extraocular muscles.

Journal Article J Muscle Res Cell Motil · June 1988 The properties of extraocular muscles (EOMs) are quite different from those of the trunk and limb. Here we show that there is a novel pattern of troponin T (TnT) expression in EOMs which most likely contributes to the fine control of ocular movement and ma ... Full text Link to item Cite

Effect of different troponin T-tropomyosin combinations on thin filament activation.

Journal Article J Mol Biol · December 5, 1987 The response of permeabilized rabbit fast skeletal muscle fibers to calcium is determined by the troponin T (TnT) and tropomyosin (Tm) isoforms they express. Fibers expressing primarily TnT2f and alpha 2 Tm exhibit steeper pCa/tension relations than those ... Full text Link to item Cite

Co-operative interactions between troponin-tropomyosin units extend the length of the thin filament in skeletal muscle.

Journal Article J Mol Biol · June 20, 1987 Ca2+ binding to troponin C (TnC), a subunit of the thin filament regulatory strand, activates vertebrate skeletal muscle contraction. Tension, however, increases with Ca2+ too abruptly to be the result of binding to sites on individual TnCs. Because extrac ... Full text Link to item Cite

Patterns of troponin T expression in mammalian fast, slow and promiscuous muscle fibres.

Journal Article J Muscle Res Cell Motil · February 1987 The distribution of troponin T (TnT) species in typed single muscle fibres was analysed using one- and two-dimensional polyacrylamide gel electrophoresis (PAGE) and a monoclonal antibody specific for fast TnT. Fibres taken from erector spinae (Es), plantar ... Full text Link to item Cite

The extent of amino-terminal heterogeneity in rabbit fast skeletal muscle troponin T.

Journal Article J Muscle Res Cell Motil · February 1987 The extent and nature of fast troponin T (TnT) heterogeneity has been assessed in rabbit skeletal muscle. Previous studies identified two major fast TnT species (TnT1f and TnT2f), in the fast white muscle erector spinae, differing in their N-terminal cyano ... Full text Link to item Cite

The moderately repetitive DNA sequences of Caenorhabditis elegans do not show short-period interspersion.

Journal Article Biochim Biophys Acta · October 24, 1978 In these studies we show that the moderately repetitive DNA sequences of Caenorhabditis elegans are not arranged in the characteristic short-period interspersion pattern of most eukaryotes. Rather, the moderately repetitive sequences are arranged in long a ... Full text Link to item Cite