Heparan sulfate is an important cell-surface carbohydrate that interacts with and regulates the activities of many molecules that influence cell growth and behavior. It is known that subtle variations in the structure of heparan sulfate control which molecules it can associate with, but little is known about how cells decide what heparan sulfate structures to make. Huy found a new way to approach this question, by using the tools of molecular biology to streamline the generation and analysis of heparan sulfate-bearing molecules (called proteoglycans) in multiple cell types.
~ Arthur D. Lander
School of Biological Sciences
In order to get first-hand experience in the practice and application of science, Huy Pham pursued a research project in developmental neurobiology. Huy found the independence and problem-solving aspects of original research to be the highlights of his experience. Ultimately, he hopes to apply these attributes to a future career in medicine. In order to create a clear direction for one's work, Huy recommends that one establishes short-term research goals.
¨ Heparan Sulfate Proteoglycans (HSPG)
¨ Alkaline Phosphatase Tagging (AP)
¨ Affinity Co-Electrophoresis (ACE)
Determination of Functionally
Specific Differences in
Heparan Sulfate Glycanation
The purpose of this study is to examine the functional significance of cell-type specific glycanation patterns of cell-surface heparan sulfate proteoglycans (HSPG). The proteoglycan (PG) of interest, glypican, was fused with alkaline phosphatase (AP) and transfected into various cell lines. Subsequent binding assays of the fusion protein were carried out with affinity co-electrophoresis (ACE), a method that allows rapid determination of a PG's binding affinity by taking advantage of its high electrical mobility. This study demonstrates that combining AP-tagging and ACE offers a convenient, systematic method of measuring the binding affinity of a specific PG, and that HS glycanation patterns influence the binding affinities of PGs against their ligands. We find that even though glypican-AP fusion proteins from Chinese hamster ovary (CHO) and 293 cells bind basic fibroblast growth factor (bFGF) and laminin-1 with similar affinities, they bind Type I collagen with significantly different affinities.
Huy Pham ~
The UCI Undergraduate Research Journal