Regulatory elements and functional implication for the formation of dimeric visinin-like protein-1.
Size exclusion chromatographic analyses showed that Ca(2+)-free VILIP-1 contained both monomeric and dimeric forms, while no appreciable dimerization was noted with Ca(2+)-free VILIP-3. Swapping of EF-hands 3 and 4 of VILIP-1 with those of VILIP-3 caused the inability of the resulting chimeric protein to form dimeric protein. Nonreducing SDS-PAGE analyses revealed that most of the dimeric VILIP-1 was noncovalently bound together. Reduced glutathione (GSH)/oxidized glutathione (GSSG) treatment notably enhanced the formation of disulfide-linked VILIP-1 dimer, while Ca(2+) and Mg(2+) enhanced disulfide dimerization of VILIP-1 marginally in the presence of thiol compounds. Cys-187 at the C-terminus of VILIP-1 contributed greatly to form S-S-crosslinked dimer as revealed by mutagenesis studies. The ability of GSH/GSSG-treated VILIP-1 to activate guanylyl cyclase B was reduced by substituting Cys-187 with Ala. Together with disulfide dimer of VILIP-1 detected in rat brain extracts, our data may imply the functional contribution of disulfide dimer to the interaction of VILIP-1 with its physiological target(s).
Chen
Ku-Chung
KC
Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Wang
Li-Kuan
LK
Chang
Long-Sen
LS
D000818:Animals; D002118:Calcium / Q000378:metabolism; D019281:Dimerization; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D016296:Mutagenesis; D051596:Neurocalcin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid
D051596:Neurocalcin; D011994:Recombinant Proteins; C496688:VSNL1 protein, human; D006162:Guanylate Cyclase; D008274:Magnesium; D002118:Calcium