Rabbit polyclonal antibody

Antigen/Purification: ExpandCollapse

Phosphopeptide corresponding to amino acid residues surrounding the phospho-Ser^23/24 of mouse troponin I, cardiac (cTnI).

Prepared from pooled rabbit serum by affinity purification via sequential chromatography on phospho and de-phosphopeptide affinity columns.

Biological Significance: ExpandCollapse

Troponin I (cTnI) is 1 of 3 subunits, along with troponin C (TnC) and troponin T (TnT) of troponin complex found in cardiac muscle. cTnI binds to actin in thin myofilaments to hold the troponin-tropomyosin complex in place. Phosphorylation of cardiac isoform of TnI at serines 22,23 in the unique amino-terminal end molecule decreases the calcium sensitivity of the sarcomere, promotes calcium dissociation from troponin C and by extension enhances rates of cross-bridge cycling and diastolic relaxation (Noland, Jr. et al., 1995; Noland et al., 1989). In addition, studies using reconstituted fibers and mutational analysis have shown that PKC phosphorylation of TnI (largely at Ser43) inhibits the actin-cross bridge reaction and reduces the Ca++ dependent actomyosin ATPase rate as well as the calcium sensitivity of force generation (Noland, Jr. and Kuo, 1991). Phosphorylation at Thr¹⁴⁴ (mediated by several PKC isoforms) reduces maximal tension development and cross-bridge cycling rates (Sumandea et al., 2008). Importantly, changes in the phosphorylation at each of these sites have been shown to be stage-specific with regard to cardiac disease progression (Walker et al., 2010).

Storage

100 μl neat serum. Adequate amount of material to conduct 10-mini Western blots.

For long term storage –20° C is recommended. Stable at –20° C for at least 1 year.

Product Specific References

Thoemmes, S. F., Stutzke, C. A., Du, Y., Browning, M. D., Buttrick, P. M., & Walker, L. A. (2014). Characterization and validation of new tools for measuring site-specific cardiac troponin I phosphorylation. Journal of immunological methods, 403(1), 66-71. PMID: 24291343