Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
1999-11-18
2003-07-29
Kunz, Gary (Department: 1647)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C435S007100, C435S007210, C435S007800, C435S007920, C435S194000, C514S002600, C514S012200
Reexamination Certificate
active
06599709
ABSTRACT:
The present invention relates generally to a novel receptor-type tyrosine kinase and to genetic sequences encoding same.
Tyrosine kinases form an important class of molecules involved in the regulation of growth and differentiation (1). One mode of proof for this role came from the identification of receptors which bind known soluble growth factors. The receptors for epidermal growth factor (EGF) (2), platelet derived growth factor (PDGF) (3) and colony stimulating factor-1 (CSF-1)(4) were all shown to be transmembrane molecules with the cytoplasmic regions encoding a tyrosine kinase catalytic domain. The CSF-1 receptor is homologous to the PDGF receptor in both the catalytic and extracellular domains (1,5). The extra cellular domain of these proteins is distinguished from other tyrosine kinases by the presence of immnunoglobulin-like repeats (1,6). Based on structural properties of the kinase domain, the c-kit protein was identified as another member of this family (7). The c-kit gene locus appears to underpin the defects in the congenitally anaemic W/W mouse (8-10). The ligand has now been identified (11-14) as shown to be encoded by the Sl locus. The locus is abnormal in the Steel mouse (15) which has identical defects to the W/W mouse but encodes a normal c-kit gene.
The other line of evidence for a critical role of tyrosine kinase proteins in growth control came from the study of viral oncogenes (16-17). These genes were shown to be directly involved in growth dysregulation by observations of a change in cell growth following introduction of DNA encoding these genes into fibroblasts. AU oncogenes have been shown to have close cellular homologues (proto-oncogenes). One of the first identified oncogenes was v-src, the cellular homologue (c-src) is the prototypical representative of the family of cytoplasmic tyrosine kinases which, following myristylation, become associated with the inner leaf of the cell membrane (18). Within the haemopoletic system a number of lineage-restricted src-like kinases have been defined (19).
The T cell-associated src-like kinase, lck, has been shown to associate independently with both the CD4 and CD8 transmembrane glycoproteins to form a signalling complex (20,21). By contrast, v-erb-B and v-fms, like their cellular homologues the EGF receptor and CSF 1 receptor, respectively, are transmembrane molecules encoding the entire signal transduction machinery in a single polypeptide (1,17).
Detailed analysis of the amino acid sequences of these proteins has revealed conserved structural motifs within the catalytic domains (5). Both tyrosine and serine-thereonine kinases have a consensus GXGXXG sequence (SEQ ID NO: 12) which is found in many nucleotide binding proteins (5). Other conserved sequence motifs are shared by both types of kinase while others are specific for the tyrosine or the threonine-serine kinase subgroups (5). The tyrosine kinases, while having regions of sequence conservation specific to this family, can be further subdivided according to the structural features of the regions 5′ to the catalytic domain (1,4-7). The novel tyrosine kinase of the present invention exhibits the same general characteristics as previously known tyrosine kinases.
In accordance with the present invention, a new receptor-type tyrosine kinase is provided and which is identified as a member of the eph/elk family of tyrosine kinases (22,23). The novel tyrosine kinase receptor is designated HEK (“human eph/elk-like kinase”). As the present inventors have identified expression of HEK in both pre-B and T cell lines, the receptor molecule of the present invention and/or its ligand is contemplated herein to have particular applicability for use as agents in the in vivo modulation of the production and/or function of pre-B, B and T cells.
Accordingly, one aspect of the present invention provides an isolated receptor-type tyrosine kinase, said tyrosine kinase characterised by, in its naturally occurring form, being reactive to the monoclonal antibody III.A4, having an apparent molecular weight of approximately 120-150 kD in the glycosylated form and having an N-terminal amino acid sequence comprising:
E L I P Q P (SEQ ID NO: 1).
Preferably, the tyrosine kinase has an N-terminal amino acid sequence comprising:
(E L I P Q P S N E V N L X D (SEQ ID NO: 2),
wherein X is any amino acid and is preferably L.
More preferably, the tyrosine kinase has an N-terminal amino acid sequence comprising the amino acids:
E L I P Q P S N E V N L X D (S) K X
1
I Q U (SEQ ID NO:3),
wherein X and X
1
are any amino acid and preferably L and T, respectively.
Even more preferably, the tyrosine kinase comprises the amino acid sequence set forth in
FIG. 1
or any parts or portions thereof, or having an amino acid sequence with at least 30% homology to the amino acid sequence set forth in FIG.
1
and having the identifying characteristics of HEK. More preferably, the degree of homology is at least 40%, still more preferably at least 55, even more preferably at least 70% and still even more preferably greater than 80%.
The hybridoma producing the monoclonal antibody III.A4 was deposited at Public Health Laboratory Service, European Collection of Animal Cell Cultures, Porton Down Salisbury, UK, on Jun. 20, 1991 under accession number 91061920.
The term “isolated” as used in relation to the tyrosine kinase of the present invention includes a biologically pure preparation comprising at least 20%, preferably at least 40%, more preferably at least 60% and even more preferably at least 80% of the protein relative to other molecules as determined by weight, activity or other convenient means. The term also encompasses any form of the protein not in the naturally occurring state such as, but not limited to, a preparation of membranes containing the protein, a preparation of the protein separate from the membrane or a supernatant fluid comprising said protein. The preparation may be glycosylated, partially unglycosylated or complete unglycosylated or may have a glycosylation pattern altered from what is naturally occurring.
The tyrosine kinase of the present invention is expressed on a number of tumours of human origin. In particular, data are presented herein showing HEK expression in human lymphoid tumour cell lines LK63, Lila-1, JM, MOLT4 and HSB-2 and the human epithelial tumour HeLa. One skilled in the art, however, will immediately recognise that similar or homologous kinases may exist on non-tumour cells or on non-human tumours and which have similar properties to the tyrosine kinase of the present invention. For example, the results contained herein show some expression of HEK in heart muscle. Accordingly, the present invention extends to a tyrosine kinase functionally and structurally similar in any or all respects to the tyrosine kinase herein described including a kinase of non-tumour origin.
The present invention extends to preparations comprising the naturally occurring form of the tyrosine kinase protein, including any naturally occurring derivative forms thereof, as well as to synthetic and recombinant forms of the protein including any single or multiple amino acid substitutions, deletions and/or insertions to the polypeptide portion of the kinase and to analogues and homologues thereof. Such amino acid alterations to the molecule are examples of recombinant or synthetic mutants and derivatives of the kinase.
Insertions include amino acid and/or carboxyl terminal fusions as weU as intra-sequence insertions of single or multiple amino acids. Generally, insertions within the amino acid sequence will be smaller than amino or carboxyl terminal fusions, of the order of say 1 to 4 residues. Insertional amino acid sequence variants are those in which one or more amino acid residues are introduced into a predetermined site in the protein. Deletional variants are characterised by the removal of one or more amino acids from the sequence. Substitutional variants are those in which at least one residue in the sequence has been removed and a different residue inserted in its place. Such subsi
Boyd Andrew W.
Simpson Richard
Ward Larry David
Wicks Ian
Wilkinson David
Kunz Gary
Scully Scott Murphy & Presser
Seharaseyon Jegatheesan
The Walter and Eliza Hall Institute of Medical Research
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