title: Interleukin-1 Receptor-Associated Kinase-1 (IRAK-1) functionally associates with PKCepsilon and VASP in the regulation of macrophage migration.
abstract: Macrophage migration is mediated by complex cellular signaling processes and cytoskeleton re-arrangement. In particular, recent advances indicate that the innate immunity signaling process plays a key role in the regulation of macrophage migration. In this report, we have provided evidence demonstrating the involvement of a key innate immunity signaling kinase, Interleukin-1 Receptor-Associated Kinase-1 (IRAK-1) as a critical modulator of macrophage migration. Macrophage migration induced by phorbol 12-myristate 13-acetate (PMA) is significantly attenuated in IRAK-1(-/-) macrophages as compared to wild type macrophages. Mechanistically, we demonstrated that IRAK-1 works downstream of PKCepsilon and upstream of VASP, a member of Ena/VASP family proteins. IRAK-1 forms a close complex with PKCepsilon as well as VASP, and participates in PMA-induced phosphorylation of VASP. Notably, IRAK-1 contains a novel EVH1 domain binding motif (L(167)WPPPP) within its N-terminus, which is responsible for its interaction with VASP. The mutant IRAK-1 (L167A/W168A) fails to associate with VASP. Our findings provide a novel facet regarding the molecular signaling process regulating macrophage migration.
authors.affiliation: Department of Biology, Virginia Tech, Blacksburg, VA 24061, USA.
authors.forename: Lu
authors.initials: L
authors.lastname: Gan
authors.forename: Liwu
authors.initials: L
authors.lastname: Li
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D053592:Interleukin-1 Receptor-Associated Kinases / Q000737:chemistry / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D051744:Protein Kinase C-epsilon / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D010768:Phosphoserine; D053592:Interleukin-1 Receptor-Associated Kinases; D051744:Protein Kinase C-epsilon; D013755:Tetradecanoylphorbol Acetate