Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1997-11-14
2003-04-01
Carlson, Karen Cochrane (Department: 1653)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S023100, C536S023600, C530S300000, C530S350000, C435S006120, C435S007100, C435S173300, C435S320100, C435S325000, C800S281000
Reexamination Certificate
active
06541615
ABSTRACT:
BACKGROUND OF THE INVENTION
Signal transduction is a fundamental mechanism whereby external stimuli are relayed to the interior of cells. A key aspect of signal transduction involves the reversible phosphorylation of tyrosine residues on proteins. The phosphorylation state of tyrosine residues on a protein is modified through the reciprocal actions of tyrosine kinases (TKs) and tyrosine phosphatases (TPs).
For example, a variety of polypeptide growth factors and hormones mediate their cellular effects by interacting with cell surface receptors and soluble or cytoplasmic polypeptide containing molecules having tyrosine kinase enzymatic activity (for review, see Williams, et al.
Cell
61:203-212 (1990); Carpenter, et al.
J. Biol. Chem
. 265:7709-7712 (1990)). The interaction of these ligands with their receptors induces a series of events which include receptor dimerization and stimulation of protein tyrosine kinase activity. Tyrosine autophosphorylation on multiple sites creates specific binding sites for target proteins, which bind to the activated receptor with their SH2 domains (for review, see Schlessinger and Ullrich,
Neuron
9:383-391, (1992)).
SH2 (src homology 2) domains are conserved sequences of about 100 amino acids found in cytoplasmic non-receptor tyrosine kinases such as pp60src, PLC-&ggr;, GAP and v-crk (Mayer, et al.,
Nature
332:272-275 (1988); Pawson,
Oncogene
3:491-495 (1988)). While having distinct catalytic domains, all these molecules share conserved SH2 and SH3 (src homology 3) domains and the ability to associate with receptors with tyrosine kinase activity (Anderson, et al.
Science
250:979-982 (1990)).
Tyrosine kinase activation and receptor autophosphorylation are prerequisites for the association between growth factor receptors and SH2 domain-containing proteins (Margolis, et al.,
Mol. Cell. Biol
. 10:435-441 (1990); Kumjian et al.,
Proc. Natl. Acad. Sci. USA
86:8232-8239 (1989); Kazlauskas, et al.,
Science
247:1578-1581 (1990)). In particular, the carboxy-terminal (C-terminal) fragment of the epidermal growth factor receptor (EGFR), which contains all the known autophosphorylation sites, binds specifically to the SH2 domains of GAP and PLC-&ggr; (see below). Hence, a major site of association exists between the SH2 domain of these substrate proteins and the tyrosine phosphorylated C-terminal tail of the EGFR.
Target proteins which bind to activated receptors have been identified by analysis of proteins that co-immunoprecipitate with growth factor receptors, or that bind to receptors attached to immobilized matrices (Morrison, et al.,
Cell
58:649-657 (1989); Kazlauskas, et al.,
EMBO J
. 9:3279-3286 (1990)).
Ohnishi et al.
J. Biol. Chem
. 271:25569-25574 (1996), not admitted to be prior art, described that a brain specific immunoglobulin-like molecule with tyrosine-based activation motifs, BIT, is associated with protein-tyrosine phosphatase SH-PTP2, whereby two SH2 domains of SH-PTP2 simultaneously interact with two phosphotyrosines of BIT-TAM.
Phosphotyrosine phosphatases (PTPs) are involved with negative or positive regulation of growth factor-specific cell responses such as mitosis, differentiation, migration, survival, transformation or death. For example, SHP-2 is a phosphotyrosine phosphatase which contains a SH2 domain. SHP-2 is a positive signal transducer for a number of receptor tyrosine kinases (RTKS) and cytokine receptors.
SUMMARY OF THE INVENTION
Within the scope of this invention, applicant has identified a novel mammalian protein family of at least fifteen members designated SIgnal Regulatory Proteins (SIRPs. In particular, Applicant has cloned and sequenced the coding sequences of 4 members of SIRPs, SIRP1 and SIRP4 from human, and SIRP&agr;1 and SIRP&bgr;1 from mouse. In this regard, the present invention relates to SIRP polypeptides, nucleic acids encoding such polypeptides, cells, tissues and animals containing such polypeptides or nucleic acids, antibodies to such polypeptides or nucleic acids, assays utilizing such polypeptides or nucleic acids, and methods relating to all of the foregoing.
SIRP family proteins play a general role in the regulation of signals that define diverse physiological and pathological processes. Thus, the present invention provides several agents and methods useful for diagnosing, treating, and preventing various diseases or conditions associated with abnormalities in these pathways as well as assay systems useful for screening for therapeutically effective agents.
In particular, SIRP polypeptides are involved in various signal transduction pathways such as the negative regulation of signals generated by receptor tyrosine kinases, including, but not limited to, receptors for EGF, insulin and platelet derived growth factor (PDGF). For example, acting like a tumor suppressor, SIRP4 exerts negative regulatory effects on growth factor and hormone induced cellular responses such as DNA synthesis. Oncogenesis may be associated with mutant SIRPs or not enough SIRPs. Restoring SIRPs to their normal levels such as by gene therapy could restore the cells to a normal growth pattern. Insulin receptor activity is also regulated by SIRPs. Overexpression of SIRPs may be involved in type II diabetes where sufficient insulin is present but insulin signaling is deficient. A compound that inhibits the negative regulation of insulin signaling by SIRPS, such as by interfering with the interaction between SIRP and SHP-2 may lead to enhanced insulin signaling.
All SIRP proteins have a receptor-like, or Immunoglubulin (Ig) like extracellular domain and a transmembrane domain. There are two subtypes of SIRPs distinguished by the presence or absence of a cytoplasmic SHP-2 binding domain. For example, SIRP4 has a cytoplasmic domain while SIRP1 doesn't. The cytoplasmic domain of SIRP4 contains two SHP-2 binding regions each having two tyrosine residues.
The growth inhibitory effect of SIRP4 depends on phosphorylation of tyrosines and is related to reduced MAP kinase activation. SIRP4 becomes a substrate of activated receptor tyrosine kinases (RTKs) upon EGF, insulin or PDGF stimulation. In its tyrosine phosphorylated form, SIRP4 binds a phosphotyrosine phosphatase, SHP-2, via SH2 interactions. Once SIRP4 binds SHP-2, it activates the catalytic activity of SHP-2 and becomes a substrate of SHP-2. This direct activation of SHP-2 could induce activation of Src or other Src family kinases. The above described interaction allows SIRP4 to participate in major signal transduction pathways involving SHP-2.
SHP-2 has two SH2 domains and is required for signaling downstream of a variety of RTKs. SHP-2 has been reported to bind directly to RTKs such as PDGF receptor, EGF receptor, and cKit in response to stimulation by their ligands. Insulin receptor substrate 1 (IRS-1) also associates with SHP-2 in response to insulin.
SIRP4 also binds SHP-1 and Grb2, both of which contain a SH-2 domain. Grb2 is an adapter molecule and one of its functions is to link growth factor receptors to downstream effector proteins. Grb2 is known to bind tyrosine-phosphorylated SHP-2 in response to PDGF stimulation.
The full length nucleic acid sequences encoding hSIRP1, hSIRP4, mSIRP&agr;1 and mSIRP&bgr;1 proteins are set forth respectively in SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, and SEQ ID NO:4. The coding regions are nt 41-1237 of SEQ ID NO:1, nt 13-1524 of SEQ ID NO:2, nt 59-1597 of SEQ ID NO:3, and nt 86-1261 of SEQ ID NO:4.
The full length amino acid sequences of hSIRP1, hSIRP4, mSIRP&agr;1 and mSIRP&bgr;1 are set forth respectively in SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, and SEQ ID NO:8. The first two Ig-like domains of hSIRP1 is from aa 54-227; the third Ig-like domain is from aa 250-330; the extracellular domain next to the membrane is from aa 336-366; and the transmembrane domain is from aa 367-398. The first two Ig-like domains of hSIRP4 is from aa 1-227; the third Ig-like domain is from aa 250-336; the extracelluar domain next to the membrane, the transmembrane domain, and the cytoplasmic domain immediate next to the membrane are f
Chen Zhengiun
Kharitonenkov Alexei
Ullrich Axel
Carlson Karen Cochrane
Foley & Lardner
Max-Planck-Gellschaft zur Foderung der Wissenschaften E.V.
Robinson Hope A.
LandOfFree
SIRP proteins and uses thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with SIRP proteins and uses thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and SIRP proteins and uses thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3101013