Ch_9_Nucleus - NUCLEUS Separates genome from the cytoplasm...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
NUCLEUS Separates genome from the cytoplasm Euk mRNAs undergo processing before being transported to the cytoplasm from the nucleus. Nuclear envelope: Separates contents of nucleus from cytoplasm Provides structural framework of nucleus 2 envelope membranes: o Inner membrane Carries proteins specific to nucleus (nuclear lamina binding proteins) o Outer membrane Continuous with (Rough) ER Functionally similar to membranes of ER Has ribosomes bound to cytoplasmic surface o Nuclear membranes act as barrier o Phospholipids bilayer permeable only to small nonpolar molec. Water and highly lipid dissolvable complexes (hormones) pass. Nuclear lamina o Fibrous meshwork that provides structural support to nucleus If degraded, nuclear envelope will collapse o Binds chromatin- DNA stuck to histones o Made up of lamins Intermediate filament proteins associate with each other to form higher order structures 2 lamins form dimer in structure called coiled coil (in parallel assembly”, dimers assoc. with each other to form the nuclear lamina. (in staggered assembly) Prenylation of C-term cysteine residues associates lamins with inner nuclear membrane. 15/20 fatty acid tail anchors lamins to inner face of inner nuclear membrane. o If lamins are phosphorylated, they can’t polymerize, so the nuclear envelope collapses. Dephosphorylation-can polymerize, so nuclear envelope forms. This occurs in the cell cycle. Nuclear pore complex o Channels for small polar molec and macromolec to pass thru envelope. o
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/19/2008 for the course MMG 409 taught by Professor Arvidson during the Spring '08 term at Michigan State University.

Page1 / 4

Ch_9_Nucleus - NUCLEUS Separates genome from the cytoplasm...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online