Contact Information

Manon Levesque Departmental Secretary of Pathology and Laboratory Medicine
451 Smyth road,
Room 4155
Ottawa, Ontario
K1H 8M5

Telephone: 613-562-5422
Fax: 613-562-5442
Email: mlevesq2@uottawa.ca

Sheila Schnupp
Office and Residency Program Administrator (Anatomical)
Telephone: 613-562-5800 ext. 8342
Fax: 613-562-5442
Email: sschnupp@uottawa.ca

John P. Veinot, M.D., F.R.C.P.C (Canada)
Chairman, Department of Pathology and Laboratory Medicine
Tel: 613-562-5422
Fax: 613-562-5442
Email: sschnupp@uottawa.ca

Back to Faculty and Staff - University of Ottawa Heart Institute page.

Zemin Yao

B.Sc. (China), M.Sc. (British Columbia), Ph.D. (ibid)

Full Professor and Chair
Department of Biochemistry, Microbiology and Immunology
Faculty of Medicine.

Cross-appointed Professor
Department of Pathology and Laboratory Medicine
Faculty of Medicine.

Member
Faculty of Graduate and Postdoctoral Studies
University of Ottawa.

Director
Molecular and Cellular Biology laboratory
University of Ottawa Heart Institute.

Telephone: 613-562-5459
Fax: 613-562-5452
Email: zyao@uOttawa.ca

Areas of Interest and Expertise

  • Factors required for hepatic assembly and secretion of apoB-containing lipoproteins.
  • The LDL-receptor binding domain(s) within human apoB100.
  • Mechanisms responsible for the intracellular degradation of newly synthesized apoB.
  • Structure/function relationships within LRP (the LDL-receptor Related Protein) and its potential role in post-prendial fat absorption by the adipose tissue.

Multifactorial analysis of hepatic VLDL assembly and secretion (funded by CIHR, 1999-2004)VLDL (very low-density lipoproteins) are macromolecules consisting of several proteins (called apoproteins) and various lipids. Assembly of VLDL occurs in the endoplasmic reticulum of the liver, but mechanism by which the apoproteins and lipids are assembled is poorly understood. Over the past, our laboratory has identified several protein factors that are essential for the assembly of hepatic VLDL, including posttranslational modification of apoB (the major apoprotein component of VLDL), MTP (microsomal triglyceride transfer protein), and iPLA2 (calcium-independent phospholipase A2). The main objective of this research project is to determine the role of these proteins at cellular and molecular levels. 

Functional analysis of structural determinants within LRP (funded by CIHR, 2001-2004) - LRP (the LDL receptor-related protein) is type I membrane protein that serves as a receptor for multiple protein ligands, including alpha-2 macroglobulin, tPA/PAI 1 and uPA/PA1 complexes, apoE, Pseudomonas exotoxin A, and others. LRP is a huge protein (4526 amino acids) whose extracellular region is composed of numerous structural modules such as "LDL receptor class A","EGF-like," and "LDL receptor YWTD". To date, the structural determinants within LRP that are responsible for its multifunctionality have not been delineated. The main purpose of this project is to delineate functional domains within LRP using recombinant DNA techniques.

HSPG-binding of Human Hepatic Lipase (funded by HSFO, 2000-2002). In humans, nearly all of the hepatic lipase (HL) is bound to cell-surface heparan sulfate proteoglycans (HSPG), and can be released into the bloodstream by heparin. We study the biochemical basis and physiological significance of cell surface association of human hepatic lipase. Human HL is synthesized primarily in the liver and is secreted into hepatic sinusoids, and becomes associated with surface of hepatocytes and endothelial cells. Deficiency in HL in human subjects is associated with premature atherosclerosis and elevated concentrations of plasma triglyceride. It is thought that human HL anchored on the liver cell surface may act as a ligand facilitating receptor-mediated endocytosis. But mechanisms whereby surface association of human HL is achieved is not fully understood. We have found that the sequences within the C-terminal 73 amino acids are important for surface binding of human HL. Currently, our research is focused on defining and characterizing sequence elements within this region using recombinant DNA technologies.

Analysis of exchangeable apolipoproteins in VLDL assembly and secretion (funded by HSFO,2001-2004). In human VLDL (very low-density lipoprotein), the major apoprotein component isthe non-exchangeable apoB100 (512 kDa) that accounts for ~50% of the total VLDL protein mass. The remainder of the VLDL protein mass consists of small (< 40 kDa), exchangeable apoproteins, including apoA-I, A-II, C-I, C-II, C-III, and E. The role of these small proteins in VLDL assembly and secretion is unclear. We have found that in transfected hepatic cell lines, expression of apoC-III is associated with increased VLDL secretion. The ongoing research is to define mechanisms whereby the expression of exchangeable apoproteins influences VLDL assembly and secretion.


Back to Faculty and Staff - University of Ottawa Heart Institute page.

© University of Ottawa
For additional information, consult our list of contacts
Technical questions? webmaster@uottawa.ca
Last updated: 2015.09.08