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-mediated muscle contraction and relaxation in the heart. Striated muscle ␣-TM is the major isoform expressed in the heart. The expression of striated muscle ␤-TM in the murine myocardium results in a decreased rate of relaxation and increased myofilament Ca 2ϩ sensitivity. Replacing the carboxyl terminus (amino acids 258 -284) of ␣-TM with ␤-TM (a troponin T-binding region) results in decreased rates of contraction and relaxation in the heart and decreased myofilament Ca 2ϩ sensitivity. We hypothesized that the putative internal troponin T-binding domain (amino acids 175-190) of ␤-TM may be responsible for the increased myofilament Ca 2ϩ sensitivity observed when the entire ␤-TM is expressed in the heart. To test this hypothesis, we generated transgenic mice that expressed chimeric TM containing ␤-TM amino acids 175-190 in the backbone of ␣-TM (amino acids 1-174 and 191-284). These mice expressed 16 -57% chimeric TM and did not develop cardiac hypertrophy or any other morphological changes. Physiological analysis showed that these hearts exhibited decreased rates of contraction and relaxation and a positive response to isoproterenol. Skinned fiber bundle analyses showed a significant increase in myofilament Ca 2ϩ sensitivity. Biophysical experiments demonstrated that the exchanged amino acids did not influence the flexibility of the TM. This is the first study to demonstrate that a specific domain within TM can increase the Ca 2ϩ sensitivity of the thin filament and affect sarcomeric performance. Furthermore, these results enhance the understanding of why TM mutations associated with familial hypertrophic cardiomyopathy demonstrate increased myofilament sensitivity to Ca 2ϩ .calcium sensitivity; contractile function; genetically altered mice TROPOMYOSIN (TM) is an essential sarcomeric protein that plays an integral role in the regulation of Ca 2ϩ -mediated striated muscle contraction. Through its interactions with the troponin (Tn) complex, TM shifts its conformational position on actin in response to Ca 2ϩ binding to TnC; this repositioning of TM on actin exposes the myosin-binding site on actin and facilitates muscle contraction. Upon cessation of stimulation, there is a resequestration of Ca 2ϩ into the sarcoplasmic reticulum and extrusion of Ca 2ϩ from the cell, resulting in TM returning to its original position as the muscle fiber relaxes.Previous studies (18,24,25) in our laboratory have established there are physiological differences among the three highly conserved striated muscle TM isoforms. The ␣-TM isoform is the predominant isoform in both skeletal and cardiac musculature in the mouse, constituting ϳ98% of total TM protein in the heart. Transgenic (TG) mice that express 50 -60% ␤-TM protein in the heart demonstrate increased sensitivity of the cardiac myofilaments to Ca 2ϩ , which leads to diastolic dysfunction (18). When ␤-TM is expressed at high levels (75-80% ␤-TM protein) in the heart, mice die due to defects in both contraction and relaxation (17). Overexpression of wild-type ␣-TM does not lea...

The regulative and oppressive effects of gender norms on bodies of transgender workers have been mostly explored in standard binary gender work settings. We explore the regulative effects of specialized transgender work regimes by posing the following two questions: How do specialized transgendered work regimes regulate transgender work and bodies? How do transgender workers cope with these regimes? Through a case study of khwajasiras, a community of male-to-female transgender people in Pakistan, we explain how competing and conflicting body ideals of hyper-eroticism, spirituality, and hybridity set by these regimes, allow khwajasiras to transgress the binary gender norms. Ironically, however, these specialized work regimes have their own regulative and oppressive effects on khwajasiras’ bodies and work. We then demonstrate how khwajasiras cope with these regulative effects in three different ways: embracing the body ideals, strategically shifting work and body across the regimes, and relegating body norms as unimportant for being a transgender. We finally argue that these differences in enacting different form of transgenderness is an outcome of a tight coupling or contradiction between audiences, khwajasira community and individual workers’ own sense of transgender authenticity.

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This case study of the restructuring of Pakistan’s garment manufacturing industry explores how attempts to increase capital’s control over the labour process intersect with local patriarchal structures and trigger workers’ reflexivity and agency causing unanticipated consequences. Using Archer’s notion of agency, the article examines the theoretical space where capitalism meets patriarchy, and both are reproduced. The focus on reflexivity, anchored between objective contexts and agents’ personal concerns, helps theorize capital–labour–gender relations in global supply chains and explains workers’ impactful resistance to protect a supposedly precarious work regime. Our findings challenge the notion that globalization reduces workers’ agency and their potential for impactful resistance.