polarised secretion Flashcards
what is the secretory pathway essential for?
growth of PM, deposition of cell wall and membrane proteins, secretion of molecules to the outside, post translational modifications
what happens when you have mutations in secretory pathway?
cell division stops but lipid syntheisis continues
what were ts sec mutants secretion blocked?
secretion of invertase and acid phosphatase
phenotype of sec 20 and 23 mutants?
large ER
phenotype of sec7 mutants
berkeley bodies- enlarged golgi
phentoype of sec1 mutants
large secretory vesicles
what is the epistatic order if events?
sec20-sec7-sec1. ER- golgi- vesicles
what are the 2 classes of early mutants
class1- vesicles to golgi. class 2- ER to golgi
what is the glycosylation of mutants blocked in ER exit?
only have core glycosylation so are smaller
what are the 5 classes of secretion mutants?
A- accumulation incytosol. no transport into ER. B- accumulation in rough ER. class C-accumulation in vesciles. D- accumulation in golgi. E-proteins accumulate in secretory vesciles
sec4 is synthetically lethal with what other proteins?
late secretory group proteins
what is sec4s GEF?
sec2
what else in sec4 dependent upon?
myo2 and actin
what protein is required for actin stability?
tropomyosin
when 1 genes for tropomyosin knocked out and other made ts, what happens at restrictive temp?
actin cables dissapear and sec4 not polarised
what are formins required for?
actin cable assembly at bud tip and neck
2 redundant formins in yeast
Bnr1 and Bni1
what proteins are in the exocyst?
sec15,3,5,6,8,10 and Exo70
what protein does sec4 physically associate with?
sec15
what is sec3 loclaisation dependent upon?
cdc42,cdc28 and rho1. not dependent upon actin cables
what does ypt31 recruit?
sec2 and 4. and activiated. also activates sec15. sec4 also recruits myo2
what does cdc42 recruit?
polarisome and actin cables are formed from this
what does the exocyst associate with?
sec4
what proteins does the exocyst bind on PM?
sec3 and exo70
