PtdIns(3,4,5)P3 binding is necessary for WAVE2-induced formation of lamellipodia.
Polarized cell movement is triggered by the development of a PtdIns(3,4,5)P(3) gradient at the membrane, which is followed by rearrangement of the actin cytoskeleton. The WASP family verprolin homologous protein (WAVE) is essential for lamellipodium formation at the leading edge by activating the Arp2/3 complex downstream of Rac GTPase. Here, we report that WAVE2 binds to PtdIns(3,4,5)P(3) through its basic domain. The amino-terminal portion of WAVE2, which includes the PtdIns(3,4,5)P(3)-binding sequence, was localized at the leading edge of lamellipodia induced by an active form of Rac (RacDA) or by treatment with platelet-derived growth factor (PDGF). Production of PtdIns(3,4,5)P(3) at the cell membrane by myristoylated phosphatidylinositol-3-OH kinase (PI(3)K) is sufficient to recruit WAVE2 in the presence of dominant-negative Rac and latrunculin, demonstrating that PtdIns(3,4,5)P(3) alone is able to recruit WAVE2. Expression of a full-length mutant of WAVE2 that lacks the lipid-binding activity inhibited proper formation of lamellipodia induced by RacDA. These results suggest that one of the products of PI(3)K, PtdIns(3,4,5)P(3), recruits WAVE2 to the polarized membrane and that this recruitment is essential for lamellipodium formation at the leading edge.
Oikawa
Tsukasa
T
Department of Biochemistry, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Yamaguchi
Hideki
H
Itoh
Toshiki
T
Kato
Masayoshi
M
Ijuin
Takeshi
T
Yamazaki
Daisuke
D
Suetsugu
Shiro
S
Takenawa
Tadaomi
T
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D011554:Pseudopodia / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D051300:Wiskott-Aldrich Syndrome Protein Family; D020744:rac GTP-Binding Proteins / Q000378:metabolism
D008840:Microfilament Proteins; D018129:Phosphatidylinositol Phosphates; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C120152:WASF2 protein, human; C492303:Wasf2 protein, mouse; D051300:Wiskott-Aldrich Syndrome Protein Family; C060974:phosphatidylinositol 3,4,5-triphosphate; D020744:rac GTP-Binding Proteins