Background: Mechanisms underlying yak adaptation to high-altitude environments have been investigated at levels of morphology, anatomy, physiology, genome and transcriptome, but not at the proteome level.
Objective: To explore for the first time the protein expression profiles in yak to reveal molecular mechanisms underlying adaptation to high altitude, up to now investigated by genome sequencing.
Methods: In the present study, an antibody microarray chip was developed, which included 6,500 mouse monoclonal antibodies. Immunoprecipitation and mass spectrometry on 12 selected antibodies showed that the chip was highly specific. Using this chip, muscle tissue proteome was compared between yak and cattle, and 12 significantly differentially expressed proteins (DEPs) were identified and their expression levels were validated by Western blot.
Results: Compared with cattle, higher levels of Rieske iron-sulfur protein (RISP), Cytochrome C oxidase subunit 4 isoform 1, mitochondrial (COX4I1), ATP synthase F1 subunit beta (ATP5F1B), Sarcoplasmic/endoplasmic reticulum calcium ATPase1 (SERCA1) and Adenosine monophosphate deaminase1 (AMPD1) in yak might increase oxygen utilization and energy metabolism. Pyruvate dehydrogenase protein X component (PDHX) and Acetyltransferase component of pyruvate dehydrogenase complex (DLAT) showed higher expression levels and L-lactate dehydrogenase A chain (LDHA) showed lower expression level, which might help yak reduce accumulation of lactic acid. In addition, higher expression levels of Filamin C (FLNC) and low levels of AHNAK and Four and a half LIM domains 1(FHL1) in yak might contribute to inhibition of pulmonary arteries vasoconstriction, remodeling and hypertension.
Conclusion: Overall, the present study reported new data at protein level in comparison between yak and cattle, which might be helpful to further understand molecular mechanisms underlying yak adaptation to high altitude environments.