Lecture 13 Flashcards
membrane around nucleus
shares border w ER
- nuclear lamina
- nuclear pores
Nuclear pores
- More than 50 different proteins (nucleoporins)
- Octagonal arrangement
- Aqueous channel - lined with fibrils
- <5000 daltons freely diffuse
what other structure can less than 5000 daltons diffuse?
porins in mitochondria
nuclear localization signals
amino acid sequence of a protein determines?
its localization
- regions w positive charge within protein sequence
- can be transported fully folded
since proteins can be transported fully folded, this is
different from protein import into other organelles
NLS sequence (nuclear localization signals)
pro-pro-lys-lys-lys-arg-lys-val
nuclear import receptors
- floating freely in cytosol
- traffick through pore is bidirectional
- have nuclear export receptors that help molecules leave nucleus
Molecules made in cytosol that are needed in the nucleus
- DNA binding proteins - histones (for packaging)
- Transcription factors
Molecules that are made in nucleus but get used in cytosol (exported)
- Ribosomal subunits made in nucleolus
- Exported for assembly into ribosomes
trafficking though unclear pore controlled by Ran
- GTPase
- found in cytosol and nucleus
Ran GAP
is cytosolic
Ran GEF
is nuclear
Spatial separation of regulatory molecules important for
function
How does Ran regulate trafficking?
- Nuclear import receptor binds to NLS on protein
- Receptor binds to FG repeats on nucleoporins and enters nucleus
- In nucleus, Ran-GTP binds to receptor - releasing cargo
- Receptor with Ran-GTP exits nucleus
- Ran-GAP hydrolyzes GTP to GDP causing release from receptor
NF cappa B
made up of what?
nuclear factor kappa B
p50 and p65. they are size.
what makes NF kappa B?
2 polypeptide chains that bind together. if you have one, you either have p50 or p65
IKK
inhibitor kappa kinase
ligand binding leads to activation of
IKK which activates more IKK’s.
p50 and p65 are bound to IKB
inhibitor of NF cappa B.
so IKB is blocking nls on NFcappaB. how can we fix this?
phosphorylate w kinase. it comes off NFkappaB.
ANTI-MÜLLERIAN HORMONE (AMH)
- hormonal control of sex differentiation in the male fetus (prevents the production of uterus and Fallopian tubes in male fetus)
FSH
7 pass transmembrane protein. Called G protein coupled receptor (alpha beta gamma associated with it)
structure of dna
Chromosomes
Genes - introns and exons
- Each cell has 2 meters of DNA
DNA
RNA
no enzymatic activity
enzymatic activity
