Cloning and characterization of mCRIP2, a mouse LIM-only protein that interacts with PDZ domain IV of PTP-BL.
BACKGROUND
In the mouse submembranous protein tyrosine phosphatase PTP-BL five PDZ domains are present in between the N-terminal FERM domain, which directs the protein to the cell cortex, and the C-terminal catalytic phosphatase domain. To understand more on the physical role of PTP-BL in this microenvironment, we started to search for PTP-BL PDZ domain-interacting proteins.


RESULTS
Yeast two-hybrid screening for PTP-BL targets resulted in the identification of a novel mouse LIM-only protein termed CRIP2 that is highly homologous to rat ESP1 and human CRP2 sequences. Mouse CRIP2 has a predicted molecular weight of 23 kD and consists of two LIM domains spaced by 68 amino acids. The fourth PDZ domain of PTP-BL is responsible for the binding of CRIP2 protein. Both PTP-BL and CRIP2 mRNAs display a wide, overlapping tissue distribution. Western blot analysis revealed a more restricted expression pattern for CRIP2 with high expression in lung, heart and brain. CRIP2 protein is localized at cell cortical, actin-rich structures, which is concurrent with the subcellular localization of PTP-BL.


CONCLUSIONS
The observed characteristics of the LIM domain-containing adaptor protein CRIP2 are consistent with a potential role of PTP-BL in the dynamics of the cortical actin cytoskeleton.
van Ham
Marco
M
Department of Cell Biology, Institute of Cellular Signalling, University Medical Center St. Radboud, University of Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands.
Croes
Huib
H
Schepens
Jan
J
Fransen
Jack
J
Wieringa
Bé
B
Hendriks
Wiljan
W
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary; D019143:Evolution, Molecular; D006801:Humans; D060588:LIM Domain Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000201:enzymology / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; C486176:CRIP2 protein, human; D018076:DNA, Complementary; D060588:LIM Domain Proteins; D009687:Nuclear Proteins; D011506:Proteins; C074370:cysteine-rich protein, mammalian; C516742:PTPN13 protein, human; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases; C516743:Ptpn13 protein, mouse