Bio 2B03 guest lecture
Why leave the cell?
• Cell signaling
• Neurotransmitters (synapses, cell communication between neurons)
• Cytokines, antibodies
• Insulin (made in pancreas and go to other cells to perform a function)
• work on budding yeast, creating individual mutants that cannot secret anything
• just one gene or multiple genes that cause a certain phenotype
• Pic 1: Mutant in A , not B , still have a viable cell
• Pic 2: Mutant in B, not A, still have a viable cell
• Pic 3: Both mutant A and B, the cell is not viable
• That suggests that both (?) or either gene A and B are required for the viability of
• Haploid yeast : sec 7 or sec 18
• Diploid yeast : sec7 + sec 18
• Haploid mate with single mutant phenotype
• sec1 (single mutant) + sec 7 (double mutant ?) >> sec 7 is upstream of sec 1.
Phenotype is of priority of sec 7 than sec 1. BB ▯sec 7 ▯sec 1
Where are sec genes involved?
• collagen is important in maintaining cell ..
• Patients with CLSD (mutation in sec23a) have large ER but cannot perform
James E. Rothman
• SNARE proteins involved in tearing of vesicles to the membrane
• important for vesicle docking
• They took cells and extract the membrane fraction. They lyse open the cell and
separate proteins from membrane bound compare to cytosol and nucleus.
• AntiMyc (antibody) epitope IgG linked to beads. They took alphaSNAP and
• Add NSF to bind to antibody?
• They were able to find a specific receptor, discovered what