| dc.description.abstract | Introduction: Ankyrin Repeat Domain 2 (ANKRD2) is expressed in skeletal muscle, where plays a role in
muscle development, differentiation and adaptation to stress. Human skeletal muscle consists of three
major fiber types: type 1 (slow-twitch, oxidative), type 2A (fast-twitch, oxidative) and type 2X (fast-twitch,
glycolytic). ANKRD2 is reported to be primarily expressed in type 1 myofibers. However, recent findings
on human single myofibers and our study of chicken muscles have shown that this protein may also be
expressed in type 2A fibers. Hence, our objective was to examine whether ANKRD2 is present in human
fast, type 2A muscle fibers using immunohistochemistry.
Methods: Samples of large leg musclessoleus, gastrocnemius, vastusintermedius and vastuslateralis were
obtained from human cadaveric tissue. Serial cryosections were independently stained with anti-ANKRD2
and antibodies for different myosin heavy chain isoforms (6H1 for type 2X, BF35 for type 1 and 2A, antiMHCs for type 1 and anti-MHCf for type 2A and 2X fibers). Immunostained tissues were analyzed by fluorescent microscopy.
Results: In addition to slow, type 1, ANKRD2 wasfound expressed in fast, type 2A myofibers, which both
have oxidative metabolism. Further, we did not observe ANDRD2 expression in glycolytic, type 2X
myiofibers. This pattern of ANKRD2 expression was consistent across all examined muscles.
Conclusion: Our resultsimplicate that the regulatory mechanism of ANKRD2 expression in human skeletal muscle is associated with oxidative metabolism, rather than muscle contraction speed. | sr |
