TAPAS-1, a novel microdomain within the unique N-terminal region of the PDE4A1 cAMP-specific phosphodiesterase that allows rapid, Ca2+-triggered membrane association with selectivity for interaction with phosphatidic acid.
Here we identify an 11-residue helical module in the unique N-terminal region of the cyclic AMP-specific phosphodiesterase PDE4A1 that determines association with phospholipid bilayers and shows a profound selectivity for interaction with phosphatidic acid (PA). This module contains a core bilayer insertion unit that is formed by two tryptophan residues, Trp(19) and Trp(20), whose orientation is optimized for bilayer insertion by the Leu(16):Val(17) pairing. Ca(2+), at submicromolar levels, interacts with Asp(21) in this module and serves to gate bilayer insertion, which is completed within 10 ms. Selectivity for interaction with PA is suggested to be achieved primarily through the formation of a charge network of the form (Asp(21-):Ca(2+):PA(2-):Lys(24+)) with overall neutrality at the bilayer surface. This novel phospholipid-binding domain, which we call TAPAS-1 (tryptophan anchoring phosphatidic acid selective-binding domain 1), is here identified as being responsible for membrane association of the PDE4A1 cAMP-specific phosphodiesterase. TAPAS-1 may not only serve as a paradigm for other PA-binding domains but also aid in detecting related phospholipid-binding domains and in generating simple chimeras for conferring membrane association and intracellular targeting on defined proteins.
Baillie
George S
GS
Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Wolfson Building, Institute of Biomedical and Life Sciences (IBLS), University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom.
Huston
Elaine
E
Scotland
Grant
G
Hodgkin
Matt
M
Gall
Irene
I
Peden
Alex H
AH
MacKenzie
Carolynn
C
Houslay
Emma S
ES
Currie
Richard
R
Pettitt
Trevor R
TR
Walmsley
Adrian R
AR
Wakelam
Michael J O
MJ
Warwicker
Jim
J
Houslay
Miles D
MD
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D007700:Kinetics; D008051:Lipid Bilayers; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection; D014364:Tryptophan
D008051:Lipid Bilayers; D010446:Peptide Fragments; D010712:Phosphatidic Acids; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014364:Tryptophan; D000242:Cyclic AMP; D015500:Chloramphenicol O-Acetyltransferase; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4