Endoplasmic reticulum physiology, bio-energetics, and life-history performance
Yap, K. N., Yamada, K., Zikeli, S., Kiaris, H., & Hood, W. R. (2021). Evaluating endoplasmic reticulum stress and unfolded protein response through the lens of ecology and evolution. Biological Reviews, 96(2), 541-556.
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Intracellular proteins carry out a multitude of biological functions that allow cells to respond to challenges posed by ever-changing environment. The endoplasmic reticulum (ER) plays a central role in synthesis, folding, modification, and transport of proteins. Proper processing of proteins requires tight regulation of ER homeostasis. ER stress occurs when cells are overloaded with unfolded or misfolded proteins and when protein production rates exceed the cells’ protein folding capacities. In response to ER stress, organisms evolved a suite of machineries that maintain proper folding and processing of intracellular proteins. However, although ER physiology is relatively well-studied in biomedical research, the study of ER physiology in the realm of ecology and evolution is understudied.
We are interested at understanding the associations between ER physiology, bio-energetics, and animals' life-history performance. Our primary research combines studies on free-living animals in the field, captive laboratory animals, as well as in vitro cultures. For studies in free-living animals, we are characterizing individual variations in ER physiology and stress responsivity, as well as investigating how ER physiology varies with life-history stages of animals. We conduct experimental studies in the lab using both animal models and cell cultures to look at how induction of ER stress affects various life-history traits, including growth and development, reproduction, bioenergetics, and physical performance. |
Comparative biology of nucleated and enucleated erythrocytes in birds and mammals
Yap, K. N., & Zhang, Y. (2021). Revisiting the question of nucleated versus enucleated erythrocytes in birds and mammals. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 321(4), R547-R557.
Main collaborator:
Yufeng Zhang (University of Memphis) |
Erythrocyte enucleation is thought to have evolved in mammals to support their energetic cost of high metabolic activities. Birds face similar selection pressure yet possess nucleated erythrocytes. Despite having nucleated erythrocytes, intracellular haemoglobin concentration of avian erythrocytes appear to be similar to enucleated mammalian erythrocytes. Hence, it appears that birds and mammals employ different evolutionary strategies to solve a common problem. However, it is unclear if possessing cell organelles within the erythrocytes confer any fitness or functional benefits to birds. Furthermore, the potential physiological functions of various cell organelles in avian erythrocytes remain unexplored.
In addition to exploring the physiological functions of various cell organelles in avian erythrocytes, we are also interested at understanding the evolutionary and physiological implications of enucleation. We take anintegrative and comparative approach, using tools from cell and molecular biology, organismal physiology, and evolutionary biology to revisit the century old idea of enucleated versus nucleated erythrocytes. |
Ecophysiology of Arctic Animals
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Animals living in the arctic are constantly exposed to harsh environmental conditions, such as cold winters, storms, and unpredictable food supply. Many of these animals have evolved a suite of physiological adaptations that allow them to cope with such environmental challenges. However, climate change has drastically altered the environment in the past few decades. This has serious impact on the animals' ability to cope with the already harsh environment, and consequently their fitness.
We are interested at understanding how individual variations in physiological and phenotypic traits relate to animals' ability to cope with environmental challenges. We are also interested in the relationships between individual variations in physiology and life-history traits such as survival and reproduction in various arctic animals. Specifically, we strive to understand how animals' ER physiology, mitochondrial physiology, metabolic hormones, and bio-energetics vary across seasons, life-history stages, and environments. |
Photos used under Creative Commons from Billy Lindblom, Tambako the Jaguar GorissM
