Loading...
Please wait, while we are loading the content...
Similar Documents
Saccharomyces cerevisiae contains a Type II phosphoinositide 4-kinase.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Shelton, Shary N. Barylko, Barbara Binns, Derk D. Horazdovsky, Bruce F. Albanesi, Joseph P. Goodman, Joel M. |
| Copyright Year | 2003 |
| Abstract | The yeast Saccharomyces cerevisiae contains two known phosphoinositide 4-kinases (PI 4-kinases), which are encoded by PIK1 and STT4; both are essential. Pik1p is important for exocytic transport from the Golgi, whereas Stt4p plays a role in cell-wall integrity and cytoskeletal rearrangements. In the present study, we report that cells have a third PI 4-kinase activity encoded by LSB6, a protein identified previously in a two-hybrid screen as interacting with LAS17p. Although Pik1p and Stt4p are closely related members of the Type III class of PI 4-kinases, Lsb6p belongs to the distinct Type II class, based on its amino acid sequence, its sensitivity to inhibition by adenosine and its insensitivity to wortmannin. Lsb6p is the first fungal Type II enzyme cloned. The protein was expressed and purified from Sf9 cells and used to define kinetic parameters. As commonly observed for surface-active enzymes, activities varied both with substrate concentration and lipid/detergent molar ratios. Maximal activities of approx. 100 min(-1) were obtained at the PI/Triton X-100 ratio of 1:5. The K (m) value for ATP was 266 microM, intermediate between the values reported for mammalian Type II and III kinases. Epitope-tagged protein, expressed in yeast, was entirely particulate, and about half of it could be extracted with non-ionic detergent. Lsb6p-green fluorescent protein was found both on vacuolar membranes and on the plasma membrane, suggesting a role in endocytic or exocytic pathways. |
| Starting Page | 1 |
| Ending Page | 5 |
| Page Count | 5 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.biochemj.org/content/ppbiochemj/371/2/533.full.pdf |
| PubMed reference number | 12523934v1 |
| Volume Number | 371 |
| Part | 2 |
| Journal | The Biochemical journal |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 1-Phosphatidylinositol-4,5-bisphosphate phosphodiesterase Adenosine Triphosphate Amino Acid Sequence Amino Acids Clone Cells DNA Sequence Rearrangement Detergents Extraction Green Fluorescent Proteins Isoelectric Point Mammals Particulate (substance) Phosphatidylinositols Plasma membrane Saccharomyces cerevisiae Staphylococcal Protein A Tissue membrane Tracer Vacuole wortmannin |
| Content Type | Text |
| Resource Type | Article |
