title: Tubulin binding protein, CacyBP/SIP, induces actin polymerization and may link actin and tubulin cytoskeletons.
abstract: CacyBP/SIP, originally identified as a S100A6 target, was shown to interact with some other S100 proteins as well as with Siah-1, Skp1, tubulin and ERK1/2 kinases (reviewed in Schneider and Filipek, Amino Acids, 2010). Here, we show that CacyBP/SIP interacts and co-localizes with actin in NB2a cells. Using a zero-length cross-linker we found that both proteins bound directly to each other. Co-sedimentation assays revealed that CacyBP/SIP induced G-actin polymerization and formation of unique circular actin filament bundles. The N-terminal fragment of CacyBP/SIP (residues 1-179) had similar effect on actin polymerization as the entire CacyBP/SIP protein, while the C-terminal one (residues 178-229) had not. To check the influence of CacyBP/SIP on cell morphology as well as on cell adhesion and migration, a stable NIH 3T3 cell line with an increased level of CacyBP/SIP was generated. We found that the adhesion and migration rates of the modified cells were changed in comparison with the control ones. Interestingly, the co-sedimentation and proximity ligation assays indicated that CacyBP/SIP could simultaneously interact with tubulin and actin, suggesting that CacyBP/SIP might link actin and tubulin cytoskeletons.
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Schneider
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Nieznanski
authors.forename: Jolanta
authors.initials: J
authors.lastname: Jozwiak
authors.forename: Lukasz P
authors.initials: LP
authors.lastname: Slomnicki
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Redowicz
authors.forename: Anna
authors.initials: A
authors.lastname: Filipek
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D007700:Kinetics; D051379:Mice; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D041681:NIH 3T3 Cells; D011108:Polymers / Q000378:metabolism; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism*
chemical_list: D000199:Actins; C111922:Cacybp protein, mouse; D002135:Calcium-Binding Proteins; D011108:Polymers; D014404:Tubulin