nuclear nuclear

Not all cells have nuclei

• Anucleate cells 

  • Skin cells 

    • Only have basal lamina cells have nucleus the rest just serve as a barrier so there is no need for a nucleus 

  • 3 lens fibers 

    • Type of fiber cell 

  • RBCS enculate 

    • Remove their nuclei 

Parts of the nucleus 

• Nuclear envelope 

  • Outer part of the nucleus 

  • 50% made up of the nuclear pores 

    • Allows diffusion for proteins less than 62 kDa 

    • Connected to the ER 

• Nucleoplasmin 

  • Pentameres w/ each subunit being 33 kDa 

    • Total of 165 kDa 

  • Functions

    • First chaperone protein discovered 

    • Genome stability 

    • Transcription regulation

    • Gets into the nucleus via ATP-dependent receptors on the nuclear pores

Lamin 

• Intermediate filaments 

• Found in the nucleus only 

• 3 main types 

  • A

  • B

  • C

• 60-70 kDa

• Interconnects chromatin to form the nuclear skeleton 

• Phosphorylation of lamin B is associated w/ dissolution of the nucleus

  • MPF phosphorylates lamin B 

Progeria 

• Prococious aging diseas 

  • Cause by rapid aging 

  • Cause by a defect in gene coding for lamin A

    • Deformed nucleus results 

      • Lamin A fornesyl group that helps lamin pack neatly 

      • Farnesyl is then cleaved off 

      • Progeria patients do not get the farnesyl group cleaved off 

Lonafarnib (drug)

• Farnesyl esterase inhibitor 

• Treatment for progeria