|Department:||School of Molecular Biosciences, WSU|
|Credentials:||1992 - Ph.D., University of Massachusetts, Zoology|
|Office:||Biotechnology Life Sciences 341|
|Mailing Address:||School of Molecular Biosciences|
PO Box 647520
Pullman, WA 99164-7520
Protein biochemistry and biology of Hsp27.
Research SummaryHsp27 is an abundant and widely distributed member of the small heat shock family of proteins and is of potential importance to normal and pathological development of reproductive tissue. Altered expression of Hsp27 has been demonstrated in ovarian, breast, and endometrial cancers and is correlated with increased tumor malignancy, altered estrogen receptor activities and enhanced resistance to chemotherapy. Normal, regulated expression of Hsp27 may be required for proper developments of male and female reproductive organs as well as spermatogenesis, and antisense inhibition of Hsp27 expression has been reported to induce redifferentiation of MCF-7 mammary carcinoma cells. The mechanism of Hsp27 function is still unclear, but proposed mechanisms include chaperone-like refolding of other denatured proteins, stabilization of contractile and structural protein complexes, altered apoptotic signaling, and reduction in cellular levels of reactive oxygen species. These activities are regulated by phosphorylation of up to three serines and s-thiolation of a single cysteine, but effects of these modifications on Hsp27 are not fully understood.
My laboratory is investigating the regulation and function of Hsp27 in developing zebrafish embryos using molecular and biochemical methods, as well as fluorescence microscopy. We recently reported that Hsp27 can associate with basolateral cell junctions in epithelial cell monolayers and co-localize with actin, at the level of the light microscope, in at epithelial cell-cell junctions and developing myofibrils. We are expressing Hsp27 mutants in zebrafish embryos and testing these mutants for their ability to interact with cytoskeletal complexes, promote survival and protect cell function from disruptions in embryos exposed to heat shock, reactive oxygen species, annoxia and a variety of environmental toxins. These studies employ fractionation followed by immunoblotting, as well as assays of apoptosis and cell survival using LDH release and fluorimetric quantification of nucleic acid content. In addition, we conduct fluorescence localization studies using immunofluorescence and analysis of expressed fluorescent fusion proteins in transiently and stably transformed fish lines.
Recently, we have also begun investigating the regulation and function of cell stress signaling pathways in cancers of the reproductive system using bioinformatics tools as well as CRISPR/Cas9 manipulation of system elements. These studies are being conducted with human cells in culture and take advantage of the myriad reagents and techniques available to the manipulation and study of cells in vitro.
Research PublicationsDhakal, S., et al. (2015). "Abnormal retinal development in Cloche mutant zebrafish." Dev Dyn 244(11): 1439-1455.
Sun, X., et al. (2014). "In vivo orientation of single myosin lever arms in zebrafish skeletal muscle." Biophys J 107(6): 1403-1414.
Kashyap, B., et al. (2014). "Eye-specific gene expression following embryonic ethanol exposure in zebrafish: roles for heat shock factor 1." Reprod Toxicol 43: 111-124.
Middleton, R. C. and E. A. Shelden (2013). "Small heat shock protein HSPB1 regulates growth of embryonic zebrafish craniofacial muscles." Exp Cell Res 319(6): 860-874.
Sanchez, E. J., et al. (2013). "Potential role of cardiac calsequestrin in the lethal arrhythmic effects of cocaine." Drug Alcohol Depend 133(2): 344-351.
Konkel, M. E., et al. (2013). "Invasion of epithelial cells by Campylobacter jejuni is independent of caveolae." Cell Commun Signal 11: 100.
Tucker, N. R., et al. (2011). "HSF1 is essential for the resistance of zebrafish eye and brain tissues to hypoxia/reperfusion injury." PLoS One 6(7): e22268.
Karlsson, A. B., E. T. Maizels, et al. (2010). "Luteinizing hormone receptor-stimulated progesterone production by preovulatory granulosa cells requires protein kinase A-dependent activation/dephosphorylation of the actin dynamizing protein cofilin." Molecular endocrinology 24(9): 1765-1781.