Kelly Tatchell, Ph.D.

Professor and Associate Dean of Graduate Studies


Contact Information:

Email: ktatch@lsuhsc.edu
Office Phone: 318-675-7769
Laboratory Phone: 318-675-4363
Office Fax: 318-675-5180

Education/Training:

Ph.D., 1978, Oregon State University

Major Research Interests:

Type 1 protein phosphatase (PP1) in the yeast Saccharomyces cerevisiae

A primary interest in our laboratory is the type 1 protein phosphatase (PP1) in the yeast Saccharomyces cerevisiae.  This evolutionarily conserved enzyme dephosphorylates phosphoserine and phosphothreonine residues on many proteins in vitro and has recently been shown to have a key regulatory role in physiological responses ranging from insulin-dependent activation of glycogen synthesis to the regulation of ion channels in the brain. The specificity of PP1 is determined by auxiliary subunits that regulate the activity of the phosphatase and target the enzyme to specific subcellular compartments.  We are using a combination of genetic and biochemical strategies to identify these regulatory subunits. Our recent focus has been the PP1 activity that opposes the Aurora B protein kinase.  This Aurora B protein kinase is essential for proper segregation of chromosomes at mitosis. We have found that cells lacking Aurora B kinase activity rapidly die from aneuploidy.  We have recently completed a genetic screen to identify mutations that compensate for a reduction in Aurora B activity.  Characterization of these mutants reveal novel mutations in the PP1 phosphatase activity that opposes Aurora B, mutations in microtubule-binding components of the kinetochore, mutations in a subunit of the Cdc48/p97 chaperone-like ATPase, and a mutation in a component of the Target of Rapamycin Complex 1 (TORC1).  TORC1 is a key regulator of cell growth control in response to nutritional signals. Our findings provide an effective means of tying cell growth control to the regulation of chromosome segregation.

Representative Publications:

  1. Saccharomyces cerevisiae Mhr1 can bind Xho I-induced mitochondrial DNA double-strand breaks in vivo.
  2. Evidence for double-strand break mediated mitochondrial DNA replication in Saccharomyces cerevisiae.
  3. Suppressors of ipl1-2 in components of a Glc7 phosphatase complex, Cdc48 AAA ATPase, TORC1, and the kinetochore.
  4. Mycobacterium tuberculosis Ku can bind to nuclear DNA damage and sensitize mammalian cells to bleomycin sulfate.
  5. Temperature-sensitive ipl1-2/Aurora B mutation is suppressed by mutations in TOR complex 1 via the Glc7/PP1 phosphatase.

All Publications: PubMed