Expression of a kinase-defective Eph-like receptor in the normal human brain.
We have identified a human Eph-family protein, HEP, gene located in human chromosomal region 7q33-->q35. The deduced amino acid sequence shared primary structural properties of Eph-family receptor tyrosine kinases. However, six invariant amino acids such as a lysine in the ATP-binding site and an aspartic acid in the phosphotransfer site of a conserved catalytic domain were substituted with other amino acid residues in HEP. Thus, no intrinsic tyrosine kinase activity was detectable in the catalytic domain expressed in CHO-K1 cell transfectants. Although most kinase-defective mutants of growth factor receptors have been reported as pathogenic receptors, its transcript was abundantly expressed in normal human adult tissues. A 135-kDa HEP protein was expressed in the human brain as much as in CHO-K1 cells transfected with a HEP cDNA expression vector. HEP is the first description of a kinase-defective Eph-family protein expressed abundantly in normal human tissues.
Matsuoka
H
H
Department of Medicine, Kobe University School of Medicine, Japan.
Iwata
N
N
Ito
M
M
Shimoyama
M
M
Nagata
A
A
Chihara
K
K
Takai
S
S
Matsui
T
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid; D001921:Brain / Q000378:metabolism*; D016466:CHO Cells; D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D017124:Conserved Sequence; D006224:Cricetinae; D029721:Drosophila Proteins; D006801:Humans; D008239:Lysine; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D036143:Receptor, EphA8; D036081:Receptors, Eph Family; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012016:Reference Values; D014162:Transfection
D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D001224:Aspartic Acid; D000255:Adenosine Triphosphate; D011494:Protein Kinases; C106797:EPHB6 protein, human; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D036143:Receptor, EphA8; D036081:Receptors, Eph Family; C117694:Hep protein, Drosophila; D020929:Mitogen-Activated Protein Kinase Kinases; D008239:Lysine