Molecular cloning of a mouse epithelial protein-tyrosine phosphatase with similarities to submembranous proteins.
Protein-tyrosine phosphatases (PTPases) form an important class of cell regulatory proteins. We have isolated overlapping cDNA clones that together comprise an 8 kb transcript encoding a novel murine PTPase which is expressed in various organs. Sequence analysis revealed an open reading frame of 2,460 amino acid residues. The predicted protein, PTP-BL, is a large non-transmembrane PTPase that exhibits 80% homology with PTP-BAS, a recently described human PTPase. PTP-BL shares some intriguing sequence homologies with submembranous proteins. It contains a band 4.1-like motif also present in the tumor suppressors neurofibromatosis 2 and expanded, five 80 amino acid repeats also present in the discs-large tumor suppressor, and a single catalytic phosphatase domain. No obvious homologies to other proteins were found for the N-terminal region of the protein other than human PTP-BAS. RNA in situ hybridization experiments show that the PTP-BL gene is expressed in epithelial cells, predominantly in kidney, lung, and skin. These data suggest a cell cortical localization for PTP-BL in epithelial cells and a possible role in the morphology and motility of epithelial tissues.
Hendriks
W
W
Department of Cell Biology and Histology, University of Nijmegen, The Netherlands.
Schepens
J
J
Bächner
D
D
Rijss
J
J
Zeeuwen
P
P
Zechner
U
U
Hameister
H
H
Wieringa
B
B
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification*; D004848:Epithelium / Q000201:enzymology; D005815:Genetic Code; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D017027:Protein Tyrosine Phosphatases