Our research interests are in the areas of the molecular biology, biochemistry, cell biology and physiology of membrane-associated proteins. The focus of our research is on the structure and function of endoplasmic reticulum (ER) membranes and the role of this membrane system in the control of intracellular signalling, communication with other intracellular organelles, regulation of proteins synthesis and folding, modulation of gene expression and Ca²⁺ homeostasis.

For several years the major emphasis of our work was on calreticulin and calnexin, a major Ca²⁺ binding and lectin-like chaperones in the ER lumen. We have now extended these studies to investigate,in a broader sense, the dynamics of the ER lumen with emphasis on protein-protein interactions, role of ions and nucleotides in the control of the ER function. Our recent transgenic and gene knockout studies indicate that ER membrane-associated proteins play an important role in embryogenesis, especially during cardiac muscle and neuronal development, physiology and pathology.

Presently our approach is to investigate the structure and function of the ER dynamics at virtually every level of biological complexity. We study purified proteins, recombinant proteins, mutants and fusion proteins. We investigate transcriptional regulation of genes encoding different ER luminal proteins. We examine the role of ER protein at the single cell level using molecular biological, biochemical, immunological and biophysical techniques. We also utilize gene knockout and transgenic techniques to examine the role of the ER proteins at the whole animal level.

The following are the main research directions of my laboratory:

1. We investigate structure/function relationships in ER proteins with a special emphasis on the dynamics of the ER luminal environment. We carry out biochemical and molecular biological investigations on the role of ER luminal proteins in control of many ER functions including ER-nucleus signalling, Ca²⁺ homeostasis, protein synthesis and folding.

2. We apply gene knockout and transgenic techniques to understand the role of ER proteins and ER luminal environment during embryogensis. We created calreticulin deficient mouse and showed that it is embryonic lethal due to a lesion in cardiac development. We applied transgenic techniques to create cardiac specific over-expressers for calreticulin. These animals develop sever cardiomyopathies, complete heart block and die from a sudden heart failure. It is likely that ER proteins may become the future targets for clinical management of complete heart block, hypertrophy and failing heart, especially in children. We are presently creating tissue-specific gene knockouts utilizing cre/LoxP techniques and conditional knockouts. We plan to extend this technique to create gene knockout and transgenic animal models for other ER luminal and integral membrane proteins.

3. We established several calreticulin and calnexin deficient stem cell lines and investigate their potential to differentiate into cardiomyocytes and/or neuronal cells. Presently, we study the role of Ca²⁺-dependent transcriptional processes in calreticulin-dependent cardiac differentiation with a special emphasis on the role of ER in the regulation of myofibrilliogenesis.

4. We use embryonic stem cells differentiation protocols to study molecular mechanisms responsible for ER-dependent tissue development and pathology.

In summary we apply biochemical, structural, biophysical techniques to investigate the structure and function of the ER associated proteins at the molecular, cell-biological, biochemical, and physiological levels.

For more information on Dr. Michalak's research, also see the Community of Science database.