title: Ankyrin repeat domain 28 (ANKRD28), a novel binding partner of DOCK180, promotes cell migration by regulating focal adhesion formation.
abstract: DOCK180 is a guanine exchange factor of Rac1 originally identified as a protein bound to an SH3 domain of the Crk adaptor protein. DOCK180 induces tyrosine phosphorylation of p130(Cas), and recruits the Crk-p130(Cas) complex to focal adhesions. To understand the role of DOCK180 in cell adhesion and migration, we searched for DOCK180-binding proteins with a nano-LC/MS/MS system, and identified ANKRD28, a protein that contains twenty-six ankyrin domain repeats. Knockdown of ANKRD28 by RNA interference reduced the velocity of migration of HeLa cells, suggesting that this protein plays a physiologic role in the DOCK180-Rac1 signaling pathway. Furthermore, knockdown of ANKRD28 was found to alter the distribution of focal adhesion proteins such as Crk, paxillin, and p130(Cas). On the other hand, expression of ANKRD28, p130(Cas), Crk, and DOCK180 induced hyper-phosphorylation of p130(Cas), and impaired detachment of the cell membrane during migration. Consequently, cells expressing ANKRD28 exhibited multiple long cellular processes. ANKRD28 associated with DOCK180 in an SH3-dependent manner and competed with ELMO, another protein bound to the SH3 domain of DOCK180. In striking contrast to ANKRD28, overexpression of ELMO induced extensive lamellipodial protrusion around the entire circumference. These data suggest that ANKRD28 specifies the localization and the activity of the DOCK180-Rac1 pathway.
authors.affiliation: Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tachibana
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kiyokawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hara
authors.forename: Shun-Ichiro
authors.initials: S
authors.lastname: Iemura
authors.forename: Tohru
authors.initials: T
authors.lastname: Natsume
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Manabe
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Matsuda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002465:Cell Movement / Q000235:genetics*; D002478:Cells, Cultured; D050719:Crk-Associated Substrate Protein / Q000378:metabolism; D022001:Focal Adhesions / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D010766:Phosphorylation / Q000235:genetics; D011485:Protein Binding; D050737:Proto-Oncogene Proteins c-crk / Q000378:metabolism; D014162:Transfection; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C514564:ANKRD28 protein, human; D048868:Adaptor Proteins, Signal Transducing; D050719:Crk-Associated Substrate Protein; C099818:DOCK1 protein, human; C465214:ELMO1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D050737:Proto-Oncogene Proteins c-crk; D020744:rac GTP-Binding Proteins