Acanthamoeba myosin IC colocalizes with phosphatidylinositol 4,5-bisphosphate at the plasma membrane due to the high concentration of negative charge.
The tail of Acanthamoeba myosin IC (AMIC) has a basic region (BR), which contains a putative pleckstrin homology (PH) domain, followed by two Gly/Pro/Ala (GPA)-rich regions separated by a Src homology 3 (SH3) domain. Cryoelectron microscopy had shown that the tail is folded back on itself at the junction of BR and GPA1, and nuclear magnetic resonance spectroscopy indicated that the SH3 domain may interact with the putative PH domain. The BR binds to acidic phospholipids, and the GPA region binds to F-actin. We now show that the folded tail does not affect the affinity of AMIC for acidic phospholipids. AMIC binds phosphatidylinositol 4,5-bisphosphate (PIP2) with high affinity (approximately 1 microm), but binding is not stereospecific. When normalized to net negative charge, AMIC binds with equal affinity to phosphatidylserine (PS) and PIP2. This and other data show that the putative PH domain of AMIC is not a typical PIP2-specific PH domain. We have identified a 13-residue sequence of basic-hydrophobic-basic amino acids within the putative PH domain that may be a major determinant of binding of AMIC to acidic phospholipids. Despite the lack of stereospecificity, AMIC binds 10 times more strongly to vesicles containing 5% PIP2 plus 25% PS than to vesicles containing only 25% PS, suggesting that AMIC may be targeted to PIP2-enriched regions of the plasma membrane. In agreement with this, AMIC colocalizes with PIP2 at dynamic, protrusive regions of the plasma membrane. We discuss the possibility that AMIC binding to PIP2 may initiate the formation of a multiprotein complex at the plasma membrane.
Brzeska
Hanna
H
Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA. brzeskah@mail.nih.gov
Hwang
Kae-Jung
KJ
Korn
Edward D
ED
D000048:Acanthamoeba / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D007477:Ions / Q000737:chemistry; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D024461:Myosin Type I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism; D011485:Protein Binding; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera
D007477:Ions; D019269:Phosphatidylinositol 4,5-Diphosphate; D010718:Phosphatidylserines; D024461:Myosin Type I
J Biol Chem. 1995 Nov 17;270(46):27969-76
7499274
Proc Natl Acad Sci U S A. 2004 Aug 17;101(33):12189-94
15302934
Cell Motil Cytoskeleton. 1998;39(2):134-46
9484955
Proc Natl Acad Sci U S A. 2006 Feb 28;103(9):3118-23
16492791
Methods Enzymol. 1991;196:12-23
1851936
J Muscle Res Cell Motil. 1997 Jun;18(3):395-8
9172081
J Biol Chem. 1988 Jan 5;263(1):427-35
2961746
Biophys J. 2004 Apr;86(4):2188-207
15041659
J Cell Biol. 1984 Jul;99(1 Pt 1):217-25
6429155
Nature. 2005 Dec 1;438(7068):605-11
16319880
Biochim Biophys Acta. 2000 Mar 17;1496(1):3-22
10722873
Trends Biochem Sci. 2001 Oct;26(10):604-11
11590013
Anal Biochem. 2004 Sep 15;332(2):261-73
15325294
Annu Rev Biophys Biomol Struct. 2002;31:151-75
11988466
J Cell Sci. 2002 Dec 15;115(Pt 24):4993-5002
12432085
J Biol Chem. 1993 Jul 15;268(20):14981-90
8325874
Eur J Cell Biol. 1996 Dec;71(4):371-9
8980908
Mol Biol Cell. 2001 Apr;12(4):780-94
11294886
EMBO J. 2004 Oct 1;23(19):3711-20
15359279
Nat Rev Mol Cell Biol. 2008 Feb;9(2):99-111
18216767
Sci STKE. 2003 Dec 16;2003(213):re16
14679290
Biochim Biophys Acta. 2006 Aug;1761(8):850-67
16807090
Mol Biol Cell. 2006 Nov;17(11):4856-65
16971510
Mol Biol Cell. 1998 Jan;9(1):75-88
9436992
J Biol Chem. 1997 Aug 29;272(35):22059-66
9268346
J Biol Chem. 1989 Nov 15;264(32):19340-8
2530230
Nature. 1993 Oct 28;365(6449):841-3
8413668
Proc Natl Acad Sci U S A. 1987 Oct;84(19):6720-4
3477803
Proc Natl Acad Sci U S A. 2007 Jan 16;104(3):784-9
17215368
Mol Cell. 2004 Mar 12;13(5):677-88
15023338
Traffic. 2003 Apr;4(4):201-13
12694559
J Biol Chem. 1986 Dec 25;261(36):17156-62
2946692
Curr Biol. 2001 Oct 30;11(21):R882-93
11696348
Science. 2006 Dec 1;314(5804):1458-61
17095657
J Biol Chem. 1998 Nov 13;273(46):30497-508
9804818
J Cell Biol. 2001 Jun 25;153(7):1479-97
11425877
FEBS Lett. 2001 Oct 12;506(3):173-9
11602240
J Cell Biol. 1990 Nov;111(5 Pt 1):1895-904
2229179
J Biol Chem. 1989 Nov 15;264(32):19333-9
2530229
Theor Biol Med Model. 2006 Mar 28;3:17
16569237
Cell Motil Cytoskeleton. 2003 Jan;54(1):29-40
12451593
J Biol Chem. 1995 Oct 27;270(43):25316-9
7592689
Proc Natl Acad Sci U S A. 1998 Dec 22;95(26):15200-5
9860946
J Biol Chem. 2001 Jan 26;276(4):2898-904
11058595
BMC Struct Biol. 2007 Jun 29;7:44
17603894
FEBS Lett. 2002 Feb 20;513(1):71-6
11911883
J Biol Chem. 2000 Aug 11;275(32):24886-92
10840041
J Cell Biol. 1992 Jun;117(6):1241-9
1607386
J Cell Biol. 1992 Dec;119(5):1193-203
1447297
J Med Chem. 2006 Oct 19;49(21):6139-42
17034116
Annu Rev Physiol. 1991;53:653-81
2042976
Cell Motil Cytoskeleton. 2004 Jul;58(3):186-99
15146537