Bio exam part 4

lysine

a ubiquitin ligase

a protein motif called degron

1/2 a ribosome

• subunits are proteases
• first ring-regulate/recognize Ubiquitin
• next rings-cleave Ub off protein/unfold

• first ring recognizes protein and unfolds
• proteases break up proteins into little oligomers (7-9 aa)

long distance, whole body differentiate responses in tissues

secreted by a cell and diffuses a short distance (~mm)

cell puts signal of its surface received by neighboring cells

feedback to same cell that produced signal

cross plasma membrane, enter cell and interact w/ receptor soluble cytoplasmic (usually) hydrophobic molecules (hormones)

or bind membrane receptor, receptor undergoes a change

small molecule binds to membrane receptor

• serine/threonine kinases (S/T)
• tyrosine kinases
• dual specificity kinases

calcium, lipids

moving molecules from place to place

• multiple steps - branched pathways
• there's tight regulation and amplification of signal

• signal transmembrane domain alpha-helix
• extracellular domain variable binds ligands
• intracellular tyrosine kinase

7-alpha helix

• 1000s of these in human genome
• diversity of receptor binding
• similar outputs

bind heterotrimeric G proteins

~100

GPCRs acts as a GEF which activates trimer and causes alpha-GTP dissociation

• they may bind to effectors, induce 2nd messenger system
• some alpha effectors serve as a GAP for the alpha proteins

• 2nd messenger kinases that phosphorylates C-terminus of receptor
• C-terminal no longer able to bring G-protein initial activation 
• signaling a lot faster than the negative feedback activity

• they are brought together and they phosphorylate each other 
• then they phosphorylate something else

• the ligand is dimeric and bring them together
• ligand disinhibits dimerization domain
• conformation change induced by ligand binding