Unit 2 Terms Flashcards
sorting signals
- Found in amino acid sequence of protein.
- New proteins must go from a ribosome in the cytosol to the organelle where it functions (knows where to go due to this signal)
electron microscopy
Helps give snapshots of the secretory pathway
RER → Golgi → Vesicles → Membrane
Sec proteins
- main proteins involved in protein trafficking
- discovered in yeast
Ribosomes initiate translation in the __________.
cytosol
Coats (for vesicles)
geometrical structures that assemble into vesicle cages
Rab Proteins vs SNARE proteins
Rab:
Guide Transport Vesicles to Their Target Membrane
SNARE:
Mediate Membrane Fusion by putting the membranes in close proximity
budding yeast Saccharomyces cerevisiae
Has a system of dispersed cisternae (not stacked like usual)
fluorescent live imaging (transport in Golgi)
- Golgi protein fused to GFP (green fluorescent protien)
- Track GFP through the Golgi
- See processes in real time and in different colors
- Fluorescence microscopy of a single cisternae shows its maturation dynamics
linear signal sequences
Sorting signals for protein translocation into organelles
nuclear envelope
two concentric membranes, perforated by nuclear pore complexes
Unstructured proteins
lack a well-structured three-dimensional fold
The concentration of Ran bound to GTP provides _______ and _____________.
Energy, directionality
Microtubule nucleation
process in which several tubulin molecules interact to form a microtubule seed
Axonal transport of organelles
Neurons transport vesicles with neurotransmitters to the synapse
Kinesin-binding ________ prevents Kinesin-_________ binding
Protein, microtubule
G actin and F actin
globular actin, filamentous actin
_______ is a drug that stabilizes F-actin. Examples? F-actin structures usually are linked to the ______.
Phalloidin
Ex: death cap mushrooms
membrane
Cells dynamically change the activity and localization of ________________ to assemble complex _____________.
actin-binding proteins, actin structures
In ______ cells, _______ are the pioneers at the leading edge which _____ the environment for cues.
Migrating, filopodia, probe
Stretch activation
intrinsic length-sensing mechanism that allows muscles to function with an autonomous regulation (bypassing calcium).
Ex: in flies
Tropomyosin vs troponin
Tropomyosin
- elongated protein that binds along the groove of the actin filament helix.
Troponin
- a complex of three polypeptides
epithelia
- cells are tightly bound together into sheets
- it’s an epithetical tissue (lining of the gut or the epidermal covering of the skin)
- selective permeability barriers
Typical cadherins vs atypical Cadherins
Typical Cadherins = Homophilic
Atypical Cadherins = heterophilic.
planar cell polarity
The collective alignment of cell polarity across the tissue plane (phenomenon)
myotendinous junctions
similar to focal adhesions but stronger and permanent
tight junctions (Cadherins)
act as ‘fences’ against transmembrane diffusion, lock the asymmetry in place.
Baz/Par-3
is a scaffold for cadherins, which then propagate the polarity in an epithelia so that all the cells are polarized equally.
The __________ proteins are the minimal ________ complex
Transmembrane, asymmetric
Non-cell autonomous effect
polarity propagates through the tissue
The ________ cellular localization of the ____ proteins is driven by a __________ but not always.
Asymmetric, core, global cue
Global pathway vs Core pathway
Global
- convert expression gradient into small asymmetries
Core
- amplify the small asymmetries into clear cellular structures
visible light spectrum
segment of the electromagnetic spectrum that the human eye can view
Photoactivatable fluorescent proteins
are fluorescent proteins that display unique changes in their spectral properties upon exposure to a specific wavelength of light
MS2/MCP system
allows tracking RNA molecules
Dicer (a nuclease enzyme)
cleaves the dsRNA into small fragments (of approximately 23 nucleotide pairs) called small interfering RNAs (siRNAs).
RNA-induced silencing complex (RISC)
a complex of ribonucleic acid and RNA-binding proteins (composed of Argonaute, RNA and etc)
A short hairpin RNA shRNA
an artificial RNA molecule with a hairpin turn that mimics a dsRNA molecule
