MSU MMG 409 EXAM 1 WITH COMPLETE SOLUTIONS
NLS - ANSWER nuclear localization signal - import INTO nucleus
NES - ANSWER nuclear export signal - export out of nucleus
On the mitochondria, plastids, and chloroplasts, where are the signal sequences always
localized? - ANSWER N-terminus (beginning of the protein)
Signal Sequence for Peroxisomes - ANSWER -Ser-Lys-Leu-COO (SSKL)
Nuclear Import Receptors (Importins) bind to... - ANSWER Nuclear localization signals
(NLS) and Nuclear pore complex (NPC) Proteins
Proteins entering the nuclear pore are... - ANSWER folded to protect it from binding to
things within the nucleus (which could cause damage)
Is the nuclear localization signal cleaved? - ANSWER NEVER! It can be reused if the
protein leave the nucleus
What is the top molecular weight of a molecule to passively diffuse across a nuclear
pore? - ANSWER 40 KDa
, What drives transport of proteins into the nucleus? - ANSWER RAN, a small GTPase
GAP - ANSWER GTPase activating protein... facilitate the hydrolysis of GTP into GDP,
inactivating a small GTPase
GEF - ANSWER guanine nucleotide exchange factor... turns GDP into GTP and activates
GTPases like RAN
Where is Ran INACTIVE? What made it inactive? - ANSWER The cytosol; inactive because
of Ran-GAP
Where is Ran ACTIVE? - ANSWER Ran moves to nucleus and is activated by Ran-GEF
To leave the nucleus, proteins require a... - ANSWER Nuclear Export Signal (NES)
Transport of proteins into mitochondria and chloroplasts occurs through... - ANSWER
TRANSLOCATORS
Proteins being transported into the mitocon. and chloroplasts ______ require metabolic
energy - ANSWER DO
Transport proteins are folded or unfolded? - ANSWER Unfolded
NLS - ANSWER nuclear localization signal - import INTO nucleus
NES - ANSWER nuclear export signal - export out of nucleus
On the mitochondria, plastids, and chloroplasts, where are the signal sequences always
localized? - ANSWER N-terminus (beginning of the protein)
Signal Sequence for Peroxisomes - ANSWER -Ser-Lys-Leu-COO (SSKL)
Nuclear Import Receptors (Importins) bind to... - ANSWER Nuclear localization signals
(NLS) and Nuclear pore complex (NPC) Proteins
Proteins entering the nuclear pore are... - ANSWER folded to protect it from binding to
things within the nucleus (which could cause damage)
Is the nuclear localization signal cleaved? - ANSWER NEVER! It can be reused if the
protein leave the nucleus
What is the top molecular weight of a molecule to passively diffuse across a nuclear
pore? - ANSWER 40 KDa
, What drives transport of proteins into the nucleus? - ANSWER RAN, a small GTPase
GAP - ANSWER GTPase activating protein... facilitate the hydrolysis of GTP into GDP,
inactivating a small GTPase
GEF - ANSWER guanine nucleotide exchange factor... turns GDP into GTP and activates
GTPases like RAN
Where is Ran INACTIVE? What made it inactive? - ANSWER The cytosol; inactive because
of Ran-GAP
Where is Ran ACTIVE? - ANSWER Ran moves to nucleus and is activated by Ran-GEF
To leave the nucleus, proteins require a... - ANSWER Nuclear Export Signal (NES)
Transport of proteins into mitochondria and chloroplasts occurs through... - ANSWER
TRANSLOCATORS
Proteins being transported into the mitocon. and chloroplasts ______ require metabolic
energy - ANSWER DO
Transport proteins are folded or unfolded? - ANSWER Unfolded
