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Published on: August 13, 2016
Acrylamide effects on kinesin-related proteins of the mitotic/meiotic spindle
Dale W Sickles1, Ann O Sperry, Angie Testino
1Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA 30912-2000, USA. dsickles@mcg.edu
Abstract:
The microtubule (MT) motor protein kinesin is a vital component of cells and organs expressing acrylamide (ACR) toxicity. As a mechanism of its potential carcinogenicity, we determined whether kinesins involved in cell division are inhibited by ACR similar to neuronal kinesin [Sickles, D.W., Brady, S.T., Testino, A.R., Friedman, M.A., and Wrenn, R.A. (1996). Direct effect of the neurotoxicant acrylamide on kinesin-based microtubule motility. Journal of Neuroscience Research 46, 7-17.] Kinesin-related genes were isolated from rat testes [Navolanic, P.M., and Sperry, A.O. (2000). Identification of isoforms of a mitotic motor in mammalian spermatogenesis. Biology of Reproduction 62, 1360-1369.], their kinesin-like proteins expressed in bacteria using recombinant DNA techniques and the effects of ACR, glycidamide (GLY) and propionamide (a non-neurotoxic metabolite) on the function of two of the identified kinesin motors were tested. KIFC5A MT bundling activity, required for mitotic spindle formation, was measured in an MT-binding assay. Both ACR and GLY caused a similar concentration-dependent reduction in the binding of MT; concentrations of 100 microM ACR or GLY reduced its activity by 60%. KRP2 MT disassembling activity was assayed using the quantity of tubulin disassembled from taxol-stabilized MT. Both ACR and GLY inhibited KRP2-induced MT disassembly. GLY was substantially more potent; significant reductions of 60% were achieved by 500 microM, a comparable inhibition by ACR required a 5 mM concentration. Propionamide had no significant effect on either kinesin, except KRP2 at 10 mM. This is the first report of ACR inhibition of a mitotic/meiotic motor protein. ACR (or GLY) inhibition of kinesin may be an alternative mechanism to DNA adduction in the production of cell division defects and potential carcinogenicity. We conclude that ACR may act on multiple kinesin family members and produce toxicities in organs highly dependent on microtubule-based functions.
Insights
Acrylamide (ACR) and its metabolite glycidamide (GLY) inhibit kinesin motor proteins crucial for cell division, suggesting a new mechanism for ACR
Area of Science:
- Molecular Biology
- Toxicology
- Cell Biology
Background:
- Kinesin is a vital microtubule (MT) motor protein involved in cellular functions.
- Acrylamide (ACR) is a known neurotoxicant, and its potential carcinogenicity is under investigation.
- Neuronal kinesin motility is affected by ACR, prompting research into its effects on cell division kinesins.
Purpose of the Study:
- To determine if ACR inhibits kinesins involved in cell division.
- To investigate the effects of ACR and its metabolites on specific kinesin motor proteins.
Main Methods:
- Kinesin-related genes were isolated from rat testes.
- Kinesin-like proteins were expressed in bacteria.
- The effects of ACR, glycidamide (GLY), and propionamide on KIFC5A MT bundling and KRP2 MT disassembly activities were tested.
Main Results:
- ACR and GLY inhibited KIFC5A MT bundling activity in a concentration-dependent manner.
- Both ACR and GLY inhibited KRP2-induced MT disassembly, with GLY being more potent.
- Propionamide showed no significant effect on either kinesin, except at high concentrations for KRP2.
Conclusions:
- This study reports for the first time the inhibition of a mitotic/meiotic motor protein by ACR.
- ACR or GLY inhibition of kinesin may contribute to cell division defects and carcinogenicity via a mechanism other than DNA adduction.
- ACR may affect multiple kinesin family members, leading to toxicities in microtubule-dependent organs.
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