Figure 3.

XIRP2, THBS4, and NCAM at the human MTJ

(A) Illustrative example of a 10-μm thick section of human semitendinosus muscle/tendon tissue from ACL patients. The myotendinous junction is marked with collagen XXII, skeletal muscle fibers “M” are stained for myosin heavy chain, and the tendon “T” is stained with tenascin (C).

(B) Strong XIRP2 (xin actin-binding repeat-containing protein 2) immunofluorescent signal confined to the myotendinous junction (MTJ) on the muscle side of the merosin (LAMA2)-stained basement membrane.

(C) Thrombospondin-4 (THBS4) immunofluorescent signal is enriched at the MTJ, located at the extracellular matrix side of the dystrophin (DMD)-stained sarcolemma.

(D) NCAM1 (neural cell adhesion molecule 1) immunofluorescent signal is concentrated in the muscle fiber cytoplasm at the MTJ. The dotted line boxes indicate areas imaged at higher magnification. Scale bars are 50 μm.