Session 9 - Lecture 1 - Protein Targeting / Collagen Biosynthesis Flashcards
1 - Title
Collagen as a example of a post-translationally modified protein
{quick 1 page brief on the diff processes – don’t need to know in masses amounts of details. all molecular detail – e.g. mitochondrial targeting – Just need to know there are things in the membrane that will transport things across.}
2 - Proteins
Proteins may be delivered to the plasma membrane via a regulated or constitutive pathway
Immunoglobulins Albumin Prohormones Collagen Fibronectin Laminin Receptors
Insulin Glucagon b-endorphin ACTH a-MSH b-lipotropin Trypsin
- Golgi apparatus
- trans Golgi network
- newly synthesised soluble proteins for constitutive secretion
- newly synthesised plasma membrane protein
- newly synthesised plasma membrane lipids
- unregulated membrane fusion
CYTOSOL
EXTRACELLULAR SPACE
CONSTITUTIVE SECRETORY PATHWAY - plasma membrane
- intracellular signalling pathway
- secretory vesicle storing secretory proteins
- regulated membrane fusion
- signal such as hormone or neurotransmitter
REGULATED SECRETORY PATHWAY
{diff types of secretion:
- constitutive (continuously) being secreted, e.g. collagen – constantly going to be producing collagen [top list]
- regulated, e.g. hormones, particular NTs – going to be released at particular times in response to a signal [bottom list]}
3 - Collagen - What is it?
Collagen
• from the Greek “kolla” meaning glue
• the most abundant protein in the body (25-35%)
• most abundant fibrous protein in connective tissue
- Tendons, ligaments, cartilage, bone
- Loose connective tissue providing structure to
internal organs
{1. Greek derivative
- a lot of it
- Find it in a lot of things bc it’s got q a lot of strength.
3b. surrounding organs.}
4 - Collagen synthesis
Secreted protein produced by fibroblasts in connective tissue
- Elastin fiber
- Fibroblasts
- Collagen fiber
Loose connective tissue - Fibroblast nuclei
- Fibroblasts
- Collagen fibers
Fibrous connective tissue
{can see it in slightly diff ways
Left: collagen fibres in loose CT – see it’s quite a lot of white blues, q diffused – other proteins as well e.g. elastins, fibroblasts whichj secrete collagen fibres that are here – fibroblast pretty small but collagen fibre is enormous compared to this – will explain later.
Right: Fibrous CT – in this case tend to see things packed full of collagen fibres – meshed between them – see this sort of idea as you look at diff sections.}
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
