Functional contribution of Ca2+ and Mg2+ to the intermolecular interaction of visinin-like proteins.
The interaction of human visinin-like protein 1 (VILIP1) and visinin-like protein 3 (VILIP3) with divalent cations (Mg2+, Ca2+, Sr2+ and Ba2+) was explored using circular dichroism and fluorescence measurement. These results showed that the four cations each induced a different subtle change in the conformation of VILIPs. Moreover, VILIP1 and VILIP3 bound with Ca2+ or Mg2+ in a cooperative manner. Studies on the truncated mutants showed that the intact EF-3 and EF-4 were essential for the binding of VILIP1 with Ca2+ and Mg2+. Pull-down assay revealed that Ca2+ and Mg2+ enhanced the intermolecular interaction of VILIPs, and led to the formation of homo- and hetero-oligomer of VILIPs. Together with previous findings that Ca2+-dependent localization of VILIPs may be involved in the regulation of distinct cascades and deprivation of Ca2+-binding capacity of VILIPs did not completely eliminate their activity, it is likely to reflect that Mg2+-bound VILIPs may play a role in regulating the biological function of VILIPs in response to a concentration fluctuation of Ca2+ in cells.
Jheng
Feng-Fin
FF
Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
Wang
Likuan
L
Lee
Liya
L
Chang
Long-Sen
LS
D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008274:Magnesium / Q000378:metabolism*; D008969:Molecular Sequence Data; D051596:Neurocalcin / Q000737:chemistry* / Q000378:metabolism*
C520235:HPCAL1 protein, human; D051596:Neurocalcin; C496688:VSNL1 protein, human; D008274:Magnesium; D002118:Calcium