Chapter 15 - Without sorting signals, they remain in the cytosol
permanently
- Cells use different strategies to isolate and organize their
- A water-soluble protein must be transported with the help
chemical reactions
of other organelles due to the hydrophilic membrane of the
- One strategy is to aggregate enzymes into multicomponent
membrane enclosed organelle it was produced in
complexes
- Proteins move into the nucleus through nucleus
- This strategy is used for synthesizing DNA, RNA, and
pores that penetrate both the inner and outer side
proteins
of the membrane. These pores are selective gates
- Another strategy is to confine different metabolic processes
and actively transport selective proteins but smaller
within membrane-enclosed compartments
molecules can diffuse easily
- This strategy is most highly developed in eukaryotic cells.
- Protein translocators in the membrane transport
MEMBRANE-ENCLOSED ORGANELLES proteins to the ER, mitochondria, and chloroplasts.
They must unfold to make it through the
- Prokaryotic cells have a single compartment enclosed by the membranes
plasma membrane - Proteins being transported by the ER are
- Eukaryotic cells are subdivided by internal membranes transferred into secretory vesicles which pinch off
- Cross section through a eukaryotic cell shows numerous from the membrane of the ER and then fuse with
membrane-enclosed organelles the organelle membrane they are transporting to
- Organelles are distinct structures that carry out specialized
functions Signal Sequences Direct Proteins to the Correct
- Each organelle contains a unique set of large and small
Compartment
molecules.
PROTEIN SORTING - A sorting signal sequence is 15-60 amino acid long
- It is removed from the protein once it is sorted
Proteins Are Transported into Organelles by Three Mechanisms - Importance of signalling sequence has been shown through
experiments where the sequence has been deleted or
- Synthesis of all proteins begins in the cytosol on the
transferred from one protein to another by genetic
ribosomes
engineering techniques
- Some mitochondrial and chloroplast proteins are made on
- Signal sequences with the same destination can look very
ribosomes inside those organelles; but most of it is made
different
outside
- The fate of any protein depends on its sorting signal
- It directs the protein to its destined organelle
permanently
- Cells use different strategies to isolate and organize their
- A water-soluble protein must be transported with the help
chemical reactions
of other organelles due to the hydrophilic membrane of the
- One strategy is to aggregate enzymes into multicomponent
membrane enclosed organelle it was produced in
complexes
- Proteins move into the nucleus through nucleus
- This strategy is used for synthesizing DNA, RNA, and
pores that penetrate both the inner and outer side
proteins
of the membrane. These pores are selective gates
- Another strategy is to confine different metabolic processes
and actively transport selective proteins but smaller
within membrane-enclosed compartments
molecules can diffuse easily
- This strategy is most highly developed in eukaryotic cells.
- Protein translocators in the membrane transport
MEMBRANE-ENCLOSED ORGANELLES proteins to the ER, mitochondria, and chloroplasts.
They must unfold to make it through the
- Prokaryotic cells have a single compartment enclosed by the membranes
plasma membrane - Proteins being transported by the ER are
- Eukaryotic cells are subdivided by internal membranes transferred into secretory vesicles which pinch off
- Cross section through a eukaryotic cell shows numerous from the membrane of the ER and then fuse with
membrane-enclosed organelles the organelle membrane they are transporting to
- Organelles are distinct structures that carry out specialized
functions Signal Sequences Direct Proteins to the Correct
- Each organelle contains a unique set of large and small
Compartment
molecules.
PROTEIN SORTING - A sorting signal sequence is 15-60 amino acid long
- It is removed from the protein once it is sorted
Proteins Are Transported into Organelles by Three Mechanisms - Importance of signalling sequence has been shown through
experiments where the sequence has been deleted or
- Synthesis of all proteins begins in the cytosol on the
transferred from one protein to another by genetic
ribosomes
engineering techniques
- Some mitochondrial and chloroplast proteins are made on
- Signal sequences with the same destination can look very
ribosomes inside those organelles; but most of it is made
different
outside
- The fate of any protein depends on its sorting signal
- It directs the protein to its destined organelle
