Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously described the purification of an 83-kDa phosphatidic acid phosphatase (PAP) from the porcine thymus membranes (Kanoh, H., Imai, S.-i., Yamada, K. and Sakane, F.(1992) J. Biol. Chem. 267, 25309-25314). However, we found that a minor 35-kDa protein could account for the PAP activity when the purified enzyme preparation was further analyzed. We thus determined the N-terminal sequence of the 35-kDa candidate protein and prepared antipeptide antibody against the determined sequence, MFDKTRLPYVALDVL. The antibody almost completely precipitated the purified enzyme activity. Furthermore, the antibody precipitated from the radioiodinated enzyme preparation a single 35-kDa protein, which was converted to a 29-kDa form when treated with N-glycanase. We also found that the immunoprecipitable PAP activity was exclusively associated with the plasma membranes of porcine thymocytes. These results indicated that the 35-kDa glycosylated protein represents the plasma membrane-bound (type 2) PAP. We surprisingly noted that the N-terminal sequence of the porcine PAP was almost completely conserved in the internal sequence encoded by a mouse partial cDNA clone, hic53, reported as a H2O2-inducible gene (Egawa, K., Yoshiwara, M., Shibanuma, M., and Nose, K.(1995) FEBS Lett. 372, 74-77). We thus amplified from the mouse kidney RNA the hic53 clone by polymerase chain reaction, and obtained a cDNA encoding a novel protein of 283 amino acid residues with a calculated Mr of 31,894. Methionine reported as an internal residue was found to serve as an initiator, and the C-terminal 64 residues were lacking in hic53. The protein contains several putative membrane-spanning domains and two N-glycosylation sites. When transfected into 293 cells, the cDNA gave more than 10-fold increase of the membrane-bound PAP activity, which could be precipitated by the antipeptide antibody. In [35S]methionine-labeled cells, the translational product was confirmed to be a 35-kDa protein, which became 30 kDa in cells treated with tunicamycin, an inhibitor of N-glycosylation. We thus succeeded first in identifying the porcine type 2 PAP and subsequently in determining the primary structure of a mouse homolog of the PAP.
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PMID:Identification and cDNA cloning of 35-kDa phosphatidic acid phosphatase (type 2) bound to plasma membranes. Polymerase chain reaction amplification of mouse H2O2-inducible hic53 clone yielded the cDNA encoding phosphatidic acid phosphatase. 870 56

To gain insight into the role of Oa1, the mouse homolog of the human X-linked ocular albinism 1 protein, its properties and subcellular localization were investigated. Antiserum raised against an expressed segment of the Oa1 protein recognized a band of approximately 48 kDa in immunoblots of extracts of cultured mouse melan-a melanocytes, but not of cells of non-melanocyte origin. When melanocyte extracts were treated with glycopeptidase F, a approximately 44 kDa band appeared. Like the melanogenic enzyme tyrosinase, expression of Oa1 was stimulated by alpha-melanocyte stimulating hormone and inhibited by agouti signal protein. Upon density gradient centrifugation of organelles of melan-a cells, Oa1 protein colocalized with the late endosomal/lysosomal marker Lamp1, but only partial overlap was observed with melanosomal proteins in the high density region of the gradient. Immunofluorescence staining revealed that neither endogenous Oa1 nor an Oa1-green fluorescent protein fusion product colocalized with the melanosomal protein tyrosinase related protein-1 in the cell periphery. In contrast, colocalization of Oa1 and Oa1-green fluorescent protein fusion product with Lamp1 was extensive throughout the cell. These results indicate that Oa1 is a melanocyte-specific integral membrane glycoprotein localized to late endosomes/lysosomes but not mature melanosomes. Considering the microscopic findings in patients with X-linked ocular albinism 1, we speculate that Oa1 may play a role in the trafficking of vesicles to developing melanosomes.
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PMID:The mouse ocular albinism 1 gene product is an endolysosomal protein. 1118 Sep 81