Characterization of a putative clone for the 67-kilodalton elastin/laminin receptor suggests that it encodes a cytoplasmic protein rather than a cell surface receptor

Abstract

The 67-kDa elastin binding protein shares many immunological and structural properties with the high-affinity 67-kDa tumor cell laminin receptor. Taking advantage of these similarities, we have screened a bovine cDNA library with a partial cDNA probe for the laminin receptor and have isolated and characterized a cDNA clone of 1038 bp that hybridizes to a single-size mRNA of 1.3 kb. The clone encodes a protein with a predicted molecular weight of 33K that lacks an N-terminal leader sequence, shows no posttranslational processing when translated in vitro in the presence of microsomes, and does not bind to elastin affinity columns. Although the bovine clone is nearly identical with clones encoding human and mouse proteins proported to be 67-kDa laminin receptor, physical and functional characteristics of the encoded protein suggest that it is a cytoplasmic protein that does not bind elastin. This finding calls into question the earlier conclusion that the clone encodes the 67-kDa receptor.

Structural determination and characterization of a 40 kDa protein isolated from rat 40 S ribosomal subunit

“…We next compared the cDNA sequence of the rat 40 kDa ribosomal protein with sequences in the EMBL data bank (release 30). The search revealed that the rat cDNA showed 52-95% identity with the cDNAs isolated as cell surface 68 kDa laminin binding protein cDNAs of human (88%) [17,18], mouse (95%) [19], bovine (88%) [20], Hydra vulgaris (54%) [21] and Drosophila melanogaster (52%) [22]. Since most of the base differences between the species were in the wobble position, the deduced amino acid sequence of the rat cDNA shared 99% identity with those of mammalian cDNAs (human, mouse and bovine) and 57-59% identity with those of cDNAs of hydra (59%) and drosophila (57%) (Fig.…”

Association of Plant p40 Protein with Ribosomes Is Enhanced When Polyribosomes Form during Periods of Active Tissue Growth

“…Vol. 11 1, 1996 previous studies that identified p40 in severa1 eukaryotic organisms as distant phylogenetically as plants (Axelos et al, 1993;García-Hernández et al, 1994), mammals (Makrides et al, 1988;McCaffery et al, 1990;Grosso et al, 1991), Hydra (Keppel and Schaller, 1991), Drosophila (Melnick et al, 1993), yeast (Davis et ai., 1992), and sea urchin (Rosenthal and Wordeman, 1995). The ubiquity of p40 in eukaryotes and the similarity among the proteins for which sequences have been deduced suggest that p40 plays a fundamental role in cell metabolism.…”

“…Initial studies identified p40 as the 67-kD laminin receptor found in vertebrate basement membranes (Wewer et al, 1986;Yow et al, 1988), although subsequent investigations have called into question the relationship between p40 and the receptor (Grosso et al, 1991;Yang et al, 1992). Lower organisms and plants are not known to contain laminin, and the majority of p40 from several species has been clearly shown to be in the cytoplasm, either in association with ribosomes (McCaffery et al, 1990;Auth and Brawerman, 1992;Davis et al, 1992;García-Hernández et al, 1994;Togho et al, 1994;Rosenthal and Wordeman, 1995) or the cytoskeleton (Keppel and Schaller, 1991).…”

“…In animals, p40 proteins and 1 or mRNAs have been identified in most tissues examined (Yenofsky et al, 1982;Rao et al, 1989;Rabacchi et al, 1990;Grosso et al, 1991;Yang et al, 1992;Melnick et al, 1993;Rosenthal and Wordeman, 1995). The protein is especially abundant in cells with high metabolic activity, such as embryonic tissues, and the mRNA was expressed preferentially in tumor cells (Yenofsky et al, 1982;Yow et al, 1988;Satoh et al, 1992).…”

Tumor shedding of laminin binding protein modulates angiostatin production in vitro and interferes with plasmin‐derived inhibition of angiogenesis in aortic ring cultures

“…55 While lacking the posttranslational processing that takes place in the native environment of eukaryotic cells, the bacterial recombinant protein appears to form a stable folded structure as evidenced by the formation of stable, protease-resistant fragments. 48 Trypsin digestion of the full-length protein results in the appearance of 1 major band at an apparent molecular weight of 23 kDa (B) and 4 lighter, less stable bands varying from 12.5 to 9 kDa (C to F) on SDS-PAGE (Fig.…”