Files in this Data Supplement:

• Supplemental Figure S1 -

  Fig. S1. Identification of myosin light chain isoforms in eastern gray squirrel left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations: MHC, myosin heavy chain; MLC1E/A, embryonic/atrial myosin light chain 1; MLC1S, MLC2S, slow-type myosin light chain 1 and 2, respectively; MLC1F, MLC2F, fast-type myosin light chain 1 and 2, respectively; MLC3, myosin light chain 3.

• Supplemental Figure S2 -

  Fig. S2. Identification of myosin light chain isoforms in eastern chipmunk left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations as in supplementary Fig. S1.

• Supplemental Figure S3 -

  Fig. S3. Identification of myosin light chain isoforms in woodchuck left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations as in supplementary Fig. S1.

• Supplemental Figure S4 -

  Fig. S4. Identification of myosin light chain isoforms in eastern fox squirrel left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations as in supplementary Fig. S1.

• Supplemental Figure S5 -

  Fig. S5. Identification of myosin light chain isoforms in southern flying squirrel left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations as in supplementary Fig. S1.

• Supplemental Figure S6 -

  Fig. S6. Identification of myosin light chain isoforms in red squirrel left ventricle (LV), left atrium (LA), masseter (MA), tibialis cranialis (TC) and soleus (SO). Lanes labeled 'I' were loaded with the non-extracted half of the same preparation (thin strips for the LV and LA, single fibers for the MA, TC and SO) from which myosin was extracted and loaded in the lanes labeled 'E'. Abbreviations as in supplementary Fig. S1.