The zinc- and calcium-binding S100B interacts and co-localizes with IQGAP1 during dynamic rearrangement of cell membranes.
The Zn(2+)- and Ca(2+)-binding S100B protein is implicated in multiple intracellular and extracellular regulatory events. In glial cells, a relationship exists between cytoplasmic S100B accumulation and cell morphological changes. We have identified the IQGAP1 protein as the major cytoplasmic S100B target protein in different rat and human glial cell lines in the presence of Zn(2+) and Ca(2+). Zn(2+) binding to S100B is sufficient to promote interaction with IQGAP1. IQ motifs on IQGAP1 represent the minimal interaction sites for S100B. We also provide evidence that, in human astrocytoma cell lines, S100B co-localizes with IQGAP1 at the polarized leading edge and areas of membrane ruffling and that both proteins relocate in a Ca(2+)-dependent manner within newly formed vesicle-like structures. Our data identify IQGAP1 as a potential target protein of S100B during processes of dynamic rearrangement of cell membrane morphology. They also reveal an additional cellular function for IQGAP1 associated with Zn(2+)/Ca(2+)-dependent relocation of S100B.
Mbele
Gaelh Ouengue
GO
Département Réponse et Différenciation Cellulaires du Commissariat à l'Energie Atomique (CEA), INSERM EMI-0104 DRDC-TS, Grenoble 38054, France.
Deloulme
Jean Christophe
JC
Gentil
Benoît Jean
BJ
Delphin
Christian
C
Ferro
Myriam
M
Garin
Jérôme
J
Takahashi
Miyoko
M
Baudier
Jacques
J
D016475:3T3 Cells; D020816:Amino Acid Motifs; D000818:Animals; D001254:Astrocytoma / Q000378:metabolism; D001665:Binding Sites; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D013058:Mass Spectrometry; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009414:Nerve Growth Factors / Q000737:chemistry* / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000737:chemistry* / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000378:metabolism; D020703:ras GTPase-Activating Proteins
D002352:Carrier Proteins; C101203:IQ motif containing GTPase activating protein 1; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; C579159:S100b protein, mouse; C579158:S100b protein, rat; D020703:ras GTPase-Activating Proteins; D015032:Zinc; D002118:Calcium