Cloning and characterization of the human retina-specific gene MPP4, a novel member of the p55 subfamily of MAGUK proteins.
To identify novel retina-specific genes systematically, we are performing expression profiling of retina ESTs that have been assembled in the human UniGene clusters. In this study, we report the 2619-bp full-length cDNA cloning and genomic organization of a gene corresponding to an EST cluster that was demonstrated to be exclusively present in retinal tissue. Alignment of the deduced amino acid sequence to sequence from protein databases revealed this gene, termed MPP4, to be a member of the membrane-associated guanylate kinase (MAGUK) protein family. It consists of 637 amino acids and contains the characteristic MAGUK motifs: an N-terminal PDZ domain, a central src homology 3 region (SH3), and a C-terminal guanylate kinase-like (GUK) domain. Due to the presence of only one PDZ motif, MPP4 is part of the p55 subfamily, named after the major palmitoylated erythrocyte membrane protein p55/MPP1. MAGUK proteins serve as molecular scaffolds to coordinate the membrane-associated cytoskeleton, ion channel and receptor clustering, signaling pathways, and the formation of cellular junctions. The abundant expression of MPP4 in the human retina suggests an important but so far unknown function in this tissue. Colocalization of MPP4 and autosomal recessive retinitis pigmentosa 26 (RP26) on chromosome 2q31-q33 makes this transcript an attractive candidate for the disease gene.
Stöhr
H
H
Institut für Humangenetik, Biozentrum, Universität Würzburg, Würzburg, D-97074, Germany.
Weber
B H
BH
D017398:Alternative Splicing; D001798:Blood Proteins / Q000235:genetics*; D015152:Blotting, Northern; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005091:Exons; D005260:Female; D015870:Gene Expression; D005796:Genes / Q000235:genetics; D051528:Guanylate Kinases; D006801:Humans; D007438:Introns; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics*; D010802:Phylogeny; D012313:RNA / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D017422:Sequence Analysis, DNA
D001798:Blood Proteins; D018076:DNA, Complementary; C089465:MPP1 protein, human; D008565:Membrane Proteins; D012313:RNA; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases