Calcium-induced conformational changes in the amino-terminal half of gelsolin.
Gelsolin is an actin-binding protein that is regulated by the occupancy of multiple calcium-binding sites. We have studied calcium induced conformational changes in the G1-2 and G1-3 sub-domains, and report the binding affinities for the three type II sites. A new probe for G3 has been produced and a K(d) of 5 microM has been measured for calcium in the context of G1-3. The two halves of gelsolin, G1-3 and G4-6 bind weakly with or without calcium, suggesting that once separated by apoptotic proteolysis, G1-3 and G4-6 remain apart allowing G1-3 to sever actin in a calcium free manner.
Roustan
Claude
C
UMR 5539 (CNRS) Laboratoire de motilité cellulaire (Ecole Pratique des Hautes Etudes), Université de Montpellier 2, Place E. Bataillon, CC107, 34095 Montpellier Cedex 5, France.
Ferjani
Imen
I
Maciver
Sutherland K
SK
Fattoum
Abdellatif
A
Rebière
Bertrand
B
Benyamin
Yves
Y
D000199:Actins / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects; D002021:Buffers; D002118:Calcium / Q000494:pharmacology*; D003619:Dansyl Compounds / Q000378:metabolism; D005453:Fluorescence; D018260:Gelsolin / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D014364:Tryptophan / Q000378:metabolism
D000199:Actins; D002021:Buffers; D003619:Dansyl Compounds; D018260:Gelsolin; D010446:Peptide Fragments; D014364:Tryptophan; D002118:Calcium