| Tissue Specificity |
Present in the basement membrane of many, but not all tissues. Expressed in retina, cochlea, small and large intestine, pancreas, bladder, prostate, esophagus, trachea, thymus, salivary glands, placenta, ovary, fallopian tube, uterus and testis. Absent in many other tissues such as heart, lung, liver, kidney and brain. In the retina, it is present in the basement membranes in the Bruch's layer choroid capillary basement membranes, where it localizes just beneath the retinal pigment epithelial cells (at protein level). Weakly expressed. Isoform 2 is expressed in fetal eye, cochlea and heart, and at very low level in brain, CNS, intestine, skeleton, tongue, kidney and lung. Isoform 2 is not expressed in stomach and liver. In adult tissues, isoform 2 is expressed in neural retina and testis, and at low level in brain, heart, kidney and liver. Isoform 1 displays a similar pattern of expression but is expressed at very low level in fetal cochlea. {ECO:0000269|PubMed:11788194, ECO:0000269|Pu
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