title: bPAK-interacting exchange factor may regulate actin cytoskeleton through interaction with actin.
abstract: p21-activated kinase (PAK)-interacting exchange factor (PIX) is known to be involved in regulation of Cdc42/Rac GTPases and PAK activity. PIX binds to the proline-rich region of PAK, and regulates biological events through activation of Cdc42/Rac GTPase. To further investigate the role of PIX we produced monoclonal antibodies (Mab) against bPIX. Three clones; N-C6 against N-terminal half and C-A3 and C-B7 against C- terminal half of bPIX were generated and characterized. N-C6 Mab detected bPIX as a major band in most cell lines. C-A3 Mab recognizes GIT-binding domain (GBD), but it does not interfere with GIT binding to bPIX. Using C-A3 Mab possible bPIX interaction with actin in PC12 cells was examined. bPIX Mab (C-A3) specifically precipitated actin of the PC12 cell lysates whereas actin Mab failed to immunoprecipitate bPIX. Co-sedimentation of PC12 cell lysates with the polymerized F-actin resulted in the recovery of most of bPIX in the cell lysates. These results suggest that bPIX may not interact with soluble actin but with polymerized F-actin and revealed that bPIX constitutes a functional complex with actin. These data indicate real usefulness of the bPIX Mab in the study of bPIX role(s) in regulation of actin cyoskeleton.
authors.affiliation: Department of Biochemistry, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 361-763 Korea.
authors.forename: Chan Soo
authors.initials: CS
authors.lastname: Lee
authors.forename: Kyung Yong
authors.initials: KY
authors.lastname: Kim
authors.forename: Jae Bin
authors.initials: JB
authors.lastname: Im
authors.forename: Jae Woon
authors.initials: JW
authors.lastname: Choi
authors.forename: Hyong Kyu
authors.initials: HK
authors.lastname: Kim
authors.forename: Jeong Soo
authors.initials: JS
authors.lastname: Park
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Shin
authors.forename: Seung Ryul
authors.initials: SR
authors.lastname: Kim
authors.forename: Eung Gook
authors.initials: EG
authors.lastname: Kim
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D018797:Cell Cycle Proteins / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D003598:Cytoskeletal Proteins / Q000378:metabolism; D018604:Epitope Mapping; D020662:Guanine Nucleotide Exchange Factors / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D047468:Immunoprecipitation; D051379:Mice; D017434:Protein Structure, Tertiary; D051381:Rats; D064067:Rho Guanine Nucleotide Exchange Factors
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D020662:Guanine Nucleotide Exchange Factors; D064067:Rho Guanine Nucleotide Exchange Factors