Elastin-laminin receptor

The true nature of this molecule has been hard to identify unequivocally, however. Recent experiments with antibodies to the 68 kDa laminin receptor have shown that it may be used as a positional marker for dorsal embryonic retina, in a variety of vertebrates (Rabacchi et al., 1990). Similar work by McCaffery et al. (1990) has shown that the dorso-ventral asymmetry of this protein has 4 peculiarities in immunoblots the molecular mass of the receptor is not 68 kDa, but 43 kDa the molecular mass of the protein deduced from cDNA is only 33 kDa (see also Auth and Brawerman, 1992) the antibodies stain a cytoplasmic antigen, not a cell surface protein and, despite the pronounced dorso-ventral difference seen after immunostaining, the 43 kDa protein identified by immunoblotting appears evenly distributed throughout the retina. The authors concluded from sequence homology that the molecule may constitute a translation-initiation factor that reflects asymmetries in some aspect of protein translation. Attempts to further characterize this receptor have been both controversial and difficult, although it is possible that it shares identity with a molecule identified as a joint elastin/laminin receptor (Martin and Timpl, 1987). 

R.P Mecham, L. Whitehouse, M. Hay, A. Hinek, M.P. Sheetz, Ligand affinity of the 67-kD elastin/laminin binding protein is modulated by the protein s lectin domain visualization of elastin/ laminin-receptor complexes with gold-tagged ligands, J. Cell Biol. 113 (1991) 187-194. 

HLE demonstrates a vast array of biologic activities besides the degradation of elastin. A partial, and by no means inclusive, list of some of these activities includes degradation of fibronectin [11], laminin [12], collagen and proteoglycans [13], and immunoglobulins (IgM, IgA and secretory IgA) [14] the activation and hydrolysis of complement components and neutrophil complement receptors [15] stimulation of mucus secretion and induction of mucous gland hypertrophy [16] and decreases in ciliary beat frequency and mucociliary clearance [17]. 

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