Rabconnectin-3-binding protein
A protein useful for clarifying the regulation mechanism of Ca 2+ -dependent exocytosis in particular, the activation and inactivation of Rab3A, and a method of screening for a material useful for regulating Ca 2+ -dependent exocytosis in particular, the activation and inactivation of Rab3A, using the above protein. By using the coimmunoprecipitation with an anti-Rab3A GEP antibody, a protein participated in the regulation of activation or inactivation of Rab3A is determined. As the protein binds to rabconnectin-3 and GDP/GTP exchange protein, it can be used for screening for a material that increases or decreases the binding.
1. A method of screening for a material that promotes or inhibits binding between a rabconnectin-3-binding protein and rabconnectin-3, comprising the steps of:
contacting a rabconnectin-3-binding protein with rabconnectin-3 in the presence and absence of a candidate material, and
determining whether the candidate material increases or decreases binding between the rabconnectin-3-binding protein and rabconnectin-3, wherein the rabconnectin-3-binding protein is a protein comprising the amino acid sequence of SEQ ID NO: 2.
2. The method of claim 1 , wherein the amino acid sequence of the rabconnectin-3-binding protein consists of the amino acid sequence of SEQ ID NO: 2.
3. A method of screening for a material that promotes or inhibits binding between a rabconnectin-3-binding protein and rabconnectin-3, comprising the steps of: contacting a rabconnectin-3-binding protein with rabconnectin-3 in the presence and absence of a candidate material, and
determining whether the candidate material increases or decreases binding between the rabconnectin-3 -binding protein and rabconnectin-3, wherein the rabconnectin-3-binding protein is a protein comprising the amino acid sequence of SEQ ID NO: 2 with one to thirty amino acids deleted, replaced, or added, and having an activity of binding rabconnectin-3 and a GDP/GTP exchange protein.
4. The method of claim 3 , wherein the rabconnectin-3-binding protein is obtained by subjecting the DNA encoding the protein comprising the amino acid sequence of SEQ ID NO: 2 to mutagenesis and selecting for a DNA encoding a mutant protein having an activity of binding rabconnectin-3 and a GDP/GTP exchange protein.