Guangjie Sun
B.S.
Tsinghua University
Department of Biological Science & Biotechnology
Project: Characterizations of the Cation-Dependent Mannose
6-Phosphate Receptor
Advisor: Dr. Nancy Dahms
There are two P-type lectins, the 46kDa mannose 6-phosphate receptor (MPR46) and the 300kDa
insulin-like growth factor II/cation-independent MPR (MPR300), that exist in virtually all
higher eukaryotes. The MPRs play an essential role in the biogenesis of lysosomes: the
receptors recognize mannose 6-phosphate (M6P)-containing lysosomal enzymes in the trans
Golgi network and transport them to acidified endosomes, thereby diverting them from the
secretory pathway. The crystal structure of the MPR46 has been solved in collaboration with
Dr. Kim and the amino acids within the binding pocket have been identified. My major interest
is to evaluate the contributions of these specific amino acids with regard to carbohydrate
recognition, especially Asp103 with regard to the receptor’s cation dependence and His105
to the receptor’s pH dependence of ligand binding.
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