#proteomics_101 Correctly label these peptide sequences as either: a) an ER signal peptide; b) a plasma membrane transporter TM domain; c) an mitochondrial inner membrane transporter TM domain or d) a type I membrane protein TM domain. Explain your choices.

#proteomics_101 AQP4:p (the CNS aquaporin) has it all: multiple PTM control points on the C-terminal cytoplasmic dynamic domain & 6 amphipathic transmembrane domains with alternating polar (yellow) & proper non-polar (FWIL) residue patches, all elegantly crammed into 5 exons.

#proteomics_101 SLC25A1:p belongs to the largest family of membrane transport proteins that move metabolites in and out of the mitochondrial matrix through its inner membrane. All of these proteins have 6 transmembrane domains that have fewer bulky hydrophobic residues than TMs in other membranes.

#proteomics_101 Human SLC7A9:p does a magic trick: it scoots cystine across the cell membrane in one direction only, using just a static distribution of polar (yellow) & nonpolar residues in its transmembrane domains. How does it work?

#proteomics_101 Human SLC2A1, an abundant monomer that smuggles very hydrophilic sugars across the very hydrophobic plasma membrane, has 12 transmembrane domains. List these domains from the most to least amphipathic. What is the significance of variations in the length of these predicted domains?

#proteomics_101 S. cerevisiae PMA2:p is predicted to have 8 transmembrane domains by some algorithms, while others find 10 TM domains. Rank the 10 predicted TM domains given below by their likelihood of being hallucinations.

#proteomics_101 Explain the differences in the pattern of observed peptides for human glial fibrillary acidic protein (GFAP:p) in disparate samples, e.g., HeLa cells vs. glioma tissue. What are the broader implications of this phenomenon?

#proteomics_101 Given what is known about the function & 3-D structures of α, β & γ catenin, propose a testable hypothesis for the difference in their propensity for K acetylation.

#proteomics_101 Compare and contrast the molecular mechanisms used to import proteins from the cytoplasm into mitochondria and the endoplasmic reticulum, including a list of at least 5 major differences between the two processes.

#proteomics_101 Provide 3 testable hypotheses about what makes the cward two thirds of yeast SED4:p (SED4, Integral ER membrane protein) disappear from most proteomics measurements.