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Parafusin: isoforms, number of genes and evolutionary origin
Author(s) -
Wyroba Elzbieta,
Liu Li,
Satir Birgit H.
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1039-a
Parafusin (PFUS) M r of 63 kDa, is a member of a superfamily of proteins, represented by the evolutionary conserved early glycolytic enzyme phosphoglucomutase (PGM) active in both glycolysis and gluconeogenesis. PFUS is a cycling phosphoglycoprotein involved in Ca 2+ ‐dependent membrane fusion and associated with secretory vesicles. It undergoes two covalent modifications: phosphoglucosylation and phosphorylation. PFUS exhibits 50.7% identity to rabbit muscle PGM (RB‐PGM), but has four insertions (1–4) and two deletions (1–2). PFUS like a few other members have negligible PGM enzymatic activity. We report here additional PFUS/PGM isoforms, number of genes in Paramecium and putative evolutionary origin. Endogenous PFUS was immunoprecipitated with pan‐PGM antibody and 2D gel and immunoblot analysis were performed using a PFUS specific peptide antibody (I‐2). Six spots at M r 63 kDa with pI’s from 6.8 to 6.3 were detected. Immunoblot analysis with the I‐2 antibody recognized only two, pI 6.7 and 6.5; these may represent the two types of PFUS posttranslational modifications. Southern blot analysis of Bgl II‐digested genomic DNA with the cloned PFUS revealed four PGM/PFUS‐related genes. To examine when in evolution this glycolytic enzyme became multi‐functional, database analysis of PFUS/ PGM sequences against archaea and eubacteria was done suggesting the divergence from PGM to PFUS in eukaryotic protist.