Premium
Resurrection of Caspase‐6 Ancestral States
Author(s) -
Grinshpon Robert D,
Clark A Clay
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.765.2
Subject(s) - biology , caspase , allosteric regulation , caspase 2 , microbiology and biotechnology , programmed cell death , genetics , apoptosis , receptor
Caspase proteins predate multicellularity. Caspases regulate cellular homeostasis by balancing cell proliferation with apoptosis. They also participate in crucial non‐apoptotic functions when their activity is regulated below an unknown apoptotic threshold. Aberrant caspase activity causes a multitude of human diseases, ranging from cancer to neurodegenerative disorders. A major obstacle to caspase research is the evolutionarily conserved active‐site structure. Cross‐reactivity of active‐site directed drugs among the family members has prevented meaningful experimentation. Thus, clinical efficacy and an understanding of sub‐threshold behavior remains elusive. Each caspase evolved unique regulatory mechanisms that determine their spatiotemporal activation and niche cellular functions. We hope to learn how these mechanisms evolved in caspases while maintaining the canonical fold and high specificity for aspartate at the P1 cleavage position. This project focuses on a unique regulatory mechanism in caspase‐6 that involves a strand‐to‐helix conformational switch. We collected over 1000 caspase protein sequences ranging from mammals to chondricthys (sharks), and performed an ancestral state reconstruction (ASR). Select ancestral states along the evolutionary path will be resurrected, and characterized in the lab with circular dichroism, activity assays and X‐ray crystallography. Preliminary data suggests that the conformational switch of caspase‐6 arose before mammals diverged, and sometime after mammals diverged from actinopterygii (fish). The mutations along the branch leading up to the neofunctionalization will shed light on how the mechanism evolved. Understanding the various natural allosteric mechanisms among caspase proteins is a crucial step to overcoming the obstacle of drug specificity, and will open up new avenues to meaningful experimentation. Large scale sequence datasets for bioinformatics analysis have recently become available to researchers. This study is a pioneer in exploring the potential of ASR to explain how evolution begets variation in protein family behavior via functional divergence.