Deducing
Functional Epitopes for GDNF Proteins and Its Specific
GFRα Co-receptors Using Phylogenetic Approach
ZHANG Qing, WANG Li-Mei1,
CHEN Zhe-Yu1, DING Da-Fu*
( Key Laboratory of Proteomics, Institute of Biochemistry
and Cell Biology, Shanghai Institutes for Biological Sciences,
the Chinese Academy of Sciences, Shanghai 200031, China;
1 Department of Neurobiology, the Second Military Medical
University, Shanghai 200433, China )
Abstract Glial cell line-derived neurotrophic
factor (GDNF) has received much attention as potential therapeutic agent for
the treatment of neurodegenerative diseases. It will be very important to
discover the molecular mechanism of this factor and its specific GFRa co-receptor. Based on the
principle of molecular evolution that site-specific functional importance is
relevant to the pressure it undergoes under natural selection, evolutionary
trace method was used to identify the functional epitopes in GDNF and GFRa families. Some trace residues
had been proved to be important in ligand-receptor binding, especially in rat
GFRa1,
where alanine scanning mutagenesis confirmed that sites N152N153, R259,
S316N317S318 and Q247D248S249 were critical for GFRa1 binding to GDNF or Ret
and thus affected the formation of GDNF-GFRa1-Ret complex.
Key
words glial cell line-derived
neurotrophic factor (GDNF) family; GFRa family; TGF-b super family; functional
epitope; evolutionary trace
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