Cloning and sequencing of parafusin, a calcium-dependent exocytosis-related phosphoglycoprotein.
A cDNA for parafusin, an evolutionarily conserved phosphoglycoprotein involved in exocytosis, has been cloned and sequenced from a unicellular eukaryote, Paramecium tetraurelia. A Paramecium cDNA library was screened with an oligonucleotide probe synthesized to an internal amino acid sequence of isolated parafusin. The insert was 3 kb long with an open reading frame of 1.75 kb. Data base searches of the deduced amino acid sequence showed that Paramecium parafusin had a 50.7% sequence identity to rabbit muscle phosphoglucomutase, although no detectable phosphoglucomutase activity has been detected in isolated parafusin. The deduced parafusin amino acid sequence had four inserts and two deletions, which might confer on the protein specific functions in signal transduction events related to exocytosis. Furthermore, searches for potential phosphorylation sites showed the presence of a protein kinase C site (KDFSFR) specific to parafusin. Southern blot analysis with probes specific for parafusin and phosphoglucomutase suggested that these proteins were products of different genes. We propose that parafusin and phosphoglucomutase are members of a superfamily that conserve homologies important for the tertiary structure of the molecules.
Subramanian
S V
SV
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461.
Wyroba
E
E
Andersen
A P
AP
Satir
B H
BH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers; D005089:Exocytosis; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D016805:Paramecium tetraurelia / Q000235:genetics / Q000378:metabolism*; D010733:Phosphoglucomutase; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000378:metabolism; D015800:Protozoan Proteins / Q000096:biosynthesis*; D011817:Rabbits; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D015345:Oligonucleotide Probes; D010750:Phosphoproteins; D015800:Protozoan Proteins; C087273:parafusin protein, Paramecium; D011493:Protein Kinase C; C488050:PGM1 protein, human; D010733:Phosphoglucomutase; D002118:Calcium