Distribution of a major lysosomal membrane glycoprotein, LGP85/LIMP II, inrat tissues

We previously identified and characterized a major lysosomal membrane glyco protcin, termed LGP85 (identical to LIMP II), in rat liver lysosomes. This study describes the distribution of the mRNA and protein of LGP85 in rat ti ssues. LGP85 protein and mRNA were detectable in all tissues when analyzed by Western and Northern blotting. The 4.2- and 2.2-kb transcripts of LGP85 were detected in all tissues. Liver and lung have the highest and lowest le vels of LGP85 mRNA, respectively. A single protein band with an apparent mo lecular weight (M-r) of similar to 85000 was detected in each tissue. The s pecific protein content of LGP85 in spleen was markedly higher than in othe r tissues. LGP85 protein is distributed in the tissues independently of LCP 85 mRNA. Furthermore, there was a less significant relationship between LGP 85 protein and another lysosomal membrane glycoprotein, lamp-1, in the tiss ue distribution (a regression coefficient of 0.086), which suggests that LG P85 may function in vivo independently of lamp-1.