Isolation of chicken phosphotyrosyl phosphatase cDNA sequences and identification of a brain-specific species related to human PTP zeta.
The first example of a chicken cDNA sequence encoding a phosphotyrosyl phosphatase (PTPase) has been identified and found to contain coding sequences for the entire cytoplasmic and membrane spanning domains as well as a portion of the extracellular region of a transmembrane PTPase resembling human PTP zeta. Like HPTP zeta, chicken PTP zeta contained two phosphatase domains (D1 and D2), and D2 lacked a critical cysteine residue required for catalytic activity. The entire intracellular portion of CPTP zeta was expressed in bacteria and shown to be capable of dephosphorylating both p-nitrophenylphosphate and reduced carboxyamidomethylated and maleyated lysozyme but not phosphoseryl casein. Genetic analysis indicated that the presence of D2 was required for full activity. CPTP zeta mRNA was identified as a single large transcript expressed exclusively in the brain of chick embryos at both early and late stages of embryogenesis. These results suggested that CPTP zeta may perform a brain-specific function and have a role in development.
Rowley
R B
RB
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Lee
J M
JM
Corbeil
H B
HB
Charbonneau
R
R
Jue
K
K
Dankort
D L
DL
Branton
P E
PE
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology*; D002642:Chick Embryo; D003001:Cloning, Molecular; D004247:DNA; D004926:Escherichia coli; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D011994:Recombinant Proteins; D004247:DNA; D017027:Protein Tyrosine Phosphatases