Isolation and characterization of ERBB3, a third member of the ERBB/epidermal growth factor receptor family: evidence for overexpression in a subset of human mammary tumors.

Abstract

A related DNA fragment distinct from the epidermal growth factor receptor and ERBB2 genes was detected by reduced stringency hybridization of v-erbB to normal genomic human DNA. Characterization of the cloned DNA fragment mapped the region of v-erbB homology to three exons with closest identity of 64% and 67% to a contiguous region within the tyrosine kinase domains of the epidermal growth factor receptor and ERBB2 proteins, respectively. cDNA cloning revealed a predicted 148-kDa transmembrane polypeptide with structural features identifying it as a member of the ERBB gene family, prompting us to designate the gene as ERBB3. It was mapped to human chromosome 12q13 and was shown to be expressed as a 6.2-kilobase transcript in a variety of normal tissues of epithelial origin. Markedly elevated ERBB3 mRNA levels were demonstrated in certain human mammary tumor cell lines. These rmdings suggest that increased ERBB3 expression, as in the case of epidermal growth factor receptor and ERBB2, may play a role in some human malignancies.Protooncogenes encoding growth factor receptors constitute several distinct families with close overall structural homology. The highest degree of homology is observed in their catalytic domains, essential for the intrinsic tyrosine kinase activity of these proteins (1). Examples of such families include genes encoding epidermal growth factor receptor (EGF-R) and ERBB2, the colony-stimulating factor 1/ platelet-derived growth factor receptors, insulin/insulin-like growth factor 1 receptors, and EPH/ELK (2-12). Growth factor receptors in several of these families play critical roles in regulation of normal growth and development. Some of these molecules have been implicated in the neoplastic process as well. In particular, both the EGF-R gene and ERBB2 have been shown to be activated as oncogenes by mechanisms involving overexpression or mutations that constitutively activate the catalytic activity of their encoded proteins (13)(14)(15)(16) DNA and RNA Hybridization. High-stringency hybridization was conducted as described (20). Reduced-stringency hybridization of DNA was carried out in 30% (vol/vol) formamide followed by washes in 0.6x SSC, whereas intermediate stringency was achieved by hybridization in 40% (vol/vol) formamide and washing in 0.25x SSC.Molecular Cloning. An oligo(dT)-primed human placenta cDNA library was obtained from Clontech. The oligo(dT) primed MCF-7 cDNA library was constructed in ApCEV9 (21). After plaque purification, phage DNA inserts were subcloned into pUC-based plasmid vectors for further characterization.Nucleotide and Amino Acid Sequence Analysis. The nucleotide sequence was determined for both DNA strands by the dideoxy chain-termination method (22) using supercoiled plasmid DNA as template.t Amino acid sequence comparison was performed with the alignment program by Pearson and Lipman (23). Hydrophobic and hydrophilic regions in the predicted protein were identified according to Kyte and Doolittle (24).

Immune responses to all ErbB family receptors detectable in serum of cancer patients

“…Anti-EGFR antiserum E7 (Fedi et al, 1994), anti-ErbB2 antiserum M6 (Alimandi et al, 1995) and antiErbB3 antiserum MK4 (Kraus et al, 1993) were raised in rabbits against synthetic peptides of the respective human coding sequence [EGFR: aa 1172 ± 1186 (Ullrich et al, 1984), ErbB2: aa 1218 ± 1232 (Yamamoto et al, 1986), ErbB3: aa 1191 ± 1205 (Kraus et al, 1989)]. ErbB4 antiserum was generated against a GST-fusion protein with the carboxyl-terminal ErbB4 domain .…”

Prolactin modulates phosphorylation, signaling and trafficking of epidermal growth factor receptor in human T47D breast cancer cells

“…EGFR, also known as ErbB-1, is the prototype of the ErbB family, which also includes ErbB-2 (c-neu, HER2), ErbB-3 and ErbB-4 (Lin et al, 1984;Bargmann et al, 1986;Kraus et al, 1989;Plowman et al, 1993). ErbB-2 has no ligand, but its basal activity is increased by EGF-like ligands.…”

Expression of dominant-negative ErbB2 in the mammary gland of transgenic mice reveals a role in lobuloalveolar development and lactation

“…Additional members of this family are the EGFR itself, ErbB3 (Kraus et al, 1989) and ErbB4 (Plowman et al, 1993). There are at least nine di erent genes that encode growth factors belonging to the epidermal growth factor (EGF)-family.…”