Automated Methods for the Analysis of Skeletal Muscle Fiber Size and Metabolic Type - International Review of Cell and Molecular Biology - page 309

Figure 7.15 Evidence for fiber type-specific protein expression in images of skeletal
muscle from the Human Protein Atlas. Top row, images are displayed for proteins which
are known to have fiber-specific expression including MyHC-

, MyHC-2A, and TNNT3
(troponin T3). Lower row, images are displayed for TRMU, PDXK, and GPATCH3, which
are proteins that have not been previously reported to be expressed in a fiber-specific
manner. Images are reproduced with permission, from the Human Protein Atlas website
( http://www.proteinatlas.org ) .

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images, and the gene IDs associated with the images were recorded. This
approach, so far, has resulted in 1131 obvious, fiber-specific images rep-
resenting 569 fiber-specific protein candidates. Examples include TRMU,
the protein whose labeling pattern correlates with the Type I fiber marker
(see above); MyHC- , in human skeletal muscle biopsies; pyridoxal kinase

(PDXK), which phosphorylates pyridoxal to form vitamin B6 which partic-
ipates in aminotransferase reactions within the mitochondria ( Depeint et al.,
2006 ); and G patch domain-containing protein 3 (GPATCH3), whose
function is yet to be identified ( Fig. 7.15 , images in lower row).
Another aspect of the HPA database is that serial sections, cut from the
same muscle sample, can often be identified via comparison of tissue section
artifacts and other features. The three lower images in Fig. 7.15 , for example,
are from the same tissue section. Interestingly, the fiber-specific distribution
of PDXK is very similar to that for TRMU (the same fibers are labeled

b