6 – Intracellular Transport
▪ Describe how proteins are localized to organelles.
▪ Describe how the ER is involved with protein synthesis,
modification, and folding.
▪ Summarize experimental procedures and evidence for
determining ER function.
▪ Predict consequences of ER dysfunction.
The SKL Sequence localizes a protein to the peroxisome.
• ___________________________________ is a frequent
motif in peroxisomal-targeting sequences (PTSs) at the C-
terminus of polypeptides.
• _____________is a PTS receptor in the cytosol.
• __________________ cargo-bearing Pex5 and Pex14
complex together to form a temporary pore for transporting
macromolecules.
• After the cargo is released, Pex5 is
___________________________ and released to the
cytosol by additional Pex enzymes.
Zellweger syndrome is rare genetic condition caused by a
mutation in the Pex5 gene. Infants born with this mutation die
less than 1 year after birth because the peroxisome is unable to
breakdown lipids, and they accumulate to lethally high levels.
Predict the reason for the complications caused by this disease.
1. Peroxisome proteins are unable to unbind from the
ribosome.
2. The peroxisome membrane is unable to form large enough
channels.
3. Peroxisome proteins are unable to enter the organelle.
4. Peroxisome proteins are unable to fold properly in the ER.
Matrix-targeting sequences target unfolded proteins to plastids.
•
________________________________________________
,
▪ Describe how proteins are localized to organelles.
▪ Describe how the ER is involved with protein synthesis,
modification, and folding.
▪ Summarize experimental procedures and evidence for
determining ER function.
▪ Predict consequences of ER dysfunction.
The SKL Sequence localizes a protein to the peroxisome.
• ___________________________________ is a frequent
motif in peroxisomal-targeting sequences (PTSs) at the C-
terminus of polypeptides.
• _____________is a PTS receptor in the cytosol.
• __________________ cargo-bearing Pex5 and Pex14
complex together to form a temporary pore for transporting
macromolecules.
• After the cargo is released, Pex5 is
___________________________ and released to the
cytosol by additional Pex enzymes.
Zellweger syndrome is rare genetic condition caused by a
mutation in the Pex5 gene. Infants born with this mutation die
less than 1 year after birth because the peroxisome is unable to
breakdown lipids, and they accumulate to lethally high levels.
Predict the reason for the complications caused by this disease.
1. Peroxisome proteins are unable to unbind from the
ribosome.
2. The peroxisome membrane is unable to form large enough
channels.
3. Peroxisome proteins are unable to enter the organelle.
4. Peroxisome proteins are unable to fold properly in the ER.
Matrix-targeting sequences target unfolded proteins to plastids.
•
________________________________________________
,
