Exam 24: Protein Trafficking

The process by which proteins are packaged and sorted is known as ___.

GEFs (guanine nucleotide exchange factors) bind to Rab and block phosphorylation of GDP. When GTP is not bound to Rab, vesicular coating and transport are inhibited.

SNARE proteins fall into the 'v' category (for ___) and 't' category (for ___).

Which would NOT be true of insulin within a pancreatic-cell? I. It would retain its KDEL signal peptide II. It would enter the Golgi with a COPI coat III. It would enter the cis Golgi from the ER IV. It would leave the ER with a clathrin coat

Similarities between myosin II and myosin V include I. presence of calmodulin II. coiled coil tail III. head group with attachment site for actin filaments IV. structural head group with ATPase domain

Myosin II binding to and subsequent dissociation from actin in muscle contraction is due to

Picturing kinesins "walking" along a microtubule, its head domains seem to act like "feet." A "step" forward is taken when the front "foot" exchanges ATP for ADP, hydrolysis occurs, and the kinesin binds to the microtubule at a site about 8 nm from its original position.

SNARE proteins have been highly characterized in

Dyneins and kinesins are similar in that

The actual movement of myosin II along actin (the "power stroke" that effects contraction) occurs

Protein synthesis occurs

The dynein microtubule binding domain contains AAA ATPase domains. ATP hydrolysis leads to tighter binding of one arm of dynein, which in turn shifts the conformation of the other arm along the microtubule.

Vesicular fusion is important in moving cargo out of the cell. Targeting particular integral proteins to the plasma membrane can also be accomplished by vesicular fusion.

One protein modification that occurs in the Golgi is the addition of mannose-6-phosphate groups through ___ bonds to ___ residues.

Bacteria

The information needed to sort proteins for trafficking resides in

Like other guanine nucleotide regulatory proteins, myosin II exchanges GDP for GTP, which sets the stage for activation. Subsequent nucleotide hydrolysis by the catalytic subunit of myosin II energizes a conformational change, which ultimately results in contraction.