The ZASP-like motif in actinin-associated LIM protein is required for interaction with the alpha-actinin rod and for targeting to the muscle Z-line.
The Z-line is a specialized structure connecting adjacent sarcomeres in muscle cells. alpha-Actinin cross-links actin filaments in the Z-line. Several PDZ-LIM domain proteins localize to the Z-line and interact with alpha-actinin. Actinin-associated LIM protein (ALP), C-terminal LIM domain protein (CLP36), and Z band alternatively spliced PDZ-containing protein (ZASP) have a conserved region named the ZASP-like motif (ZM) between PDZ and LIM domains. To study the interactions and function of ALP we used purified recombinant proteins in surface plasmon resonance measurements. We show that ALP and alpha-actinin 2 have two interaction sites. The ZM motif was required for the interaction of ALP internal region with the alpha-actinin rod and for targeting of ALP to the Z-line. The PDZ domain of ALP bound to the C terminus of alpha-actinin. This is the first indication that the ZM motif would have a direct role in a protein-protein interaction. These results suggest that the two interaction sites of ALP would stabilize certain conformations of alpha-actinin 2 that would strengthen the Z-line integrity.
Klaavuniemi
Tuula
T
Biocenter Oulu and Department of Biochemisty, University of Oulu, P. O. Box 3000, FIN-90014 Oulu, Finland.
Kelloniemi
Annina
A
Ylänne
Jari
J
D000185:Actinin / Q000737:chemistry* / Q000378:metabolism; D000199:Actins / Q000737:chemistry; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D060588:LIM Domain Proteins; D051379:Mice; D008840:Microfilament Proteins / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D018482:Muscle, Skeletal / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D020349:Surface Plasmon Resonance; D013997:Time Factors
D000199:Actins; D018076:DNA, Complementary; D018398:Homeodomain Proteins; D060588:LIM Domain Proteins; D008840:Microfilament Proteins; C108834:PDLIM3 protein, human; C097168:Pdlim1 protein, rat; C484642:Pdlim3 protein, mouse; D010455:Peptides; D011994:Recombinant Proteins; D000185:Actinin