Download MBBS Trafficking of Protein II Lecture PPT

Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Trafficking of Protein II Lecture PPT


Transport into the nucleus









? Proteins similar to importins, referred to as exportins, are

involved in the export of

many macromolecules (various

proteins, tRNA molecules, ribosomal subunits and
certain mRNA molecules) from the nucleus

? Cargo molecules for export carry nuclear export signals

(NESs).

? Ran proteins are involved in this process also
? The family of importins and exportins are referred to as

karyopherins

? Another system is involved in the translocation of the

majority of mRNA molecules.

? These are exported from the nucleus to the cytoplasm as

ribonucleoprotein (RNP) complexes attached to a protein
named mRNP exporter


Peroxisomes


Transport into peroxisomes
Transport into peroxisomes

? Peroxins - peroxisome transport receptors
? Bind to proteins with PTS1 and dock to the

translocation channel

? The complex is transported through the membrane
? Protein is released
? Peroxin is recycled



Zellweger syndrome

? Usually caused by mutations in genes encoding certain

proteins--the PEX family of genes, also called peroxins

--involved in various steps of peroxisome biogenesis

? Number of peroxisomes can vary from being almost

normal to being virtually absent in some patients

? Apparent at birth and is characterized by profound

neurologic impairment, victims often dying within a year

? Biochemical findings include an accumulation of very-

long-chain fatty acids, abnormalities of the synthesis of

bile acids, and a marked reduction of plasmalogens

? Two closely related conditions are neonatal

adrenoleukodystrophy and infantile Refsum disease.

This post was last modified on 30 November 2021