This document discusses cellular vesicles and membrane trafficking. It defines vesicles as membranous sacs that store and transport cellular products or waste. There are three main types of vesicles: secretory vesicles, transport vesicles, and storage vesicles. The document then discusses the mechanisms and proteins involved in vesicle formation, transport, and fusion, including endocytosis, exocytosis, clathrin, adaptor proteins, dynamin, Rab GTPases, and SNARE proteins. It also mentions some diseases related to problems in vesicle trafficking like botulism, tetanus, and familial hypercholesterolemia.

2.  bubble-like membranous
structure that stores and
transports cellular
products, and digests
metabolic wastes within
the cell;
 an intracellular
membranous sac that is
separated from
the cytosol by at least one
lipid bilayer.
 Secretory Vesicles
 Transport Vesicles
 Storage Vesicles

3.  Transport across but not through the
membrane
 Mode of transport of macromolecules
 Requires metabolic energy but is independent
of concentration gradient

4.  ENDOCYTOSIS
 EXOCYTOSIS
 TRANSCYTOSIS

5.  TYPES
Phagocytosis- cell eating
Pinocytosis- cell drinking
Receptor-mediated

6. Mechanisms :
 Constitutive Pathway
 Clathrin-mediated Pathway
internalization of many receptors and
the ligands bound to them—including, for
example, nerve growth factor and low-
density lipoproteins

7.  Clathrin coated vesicles – COP I & COP II
 Clathrin
 Adaptor Proteins
 Dynamin
Pinchase

9. Non-Constitutive / Regulated Pathway
Constitutive Pathway
Exocytosis-Endocytosis coupling
maintains the surface area of the cell
at its normal size.

10. Biosynthetic-
Secretory pathway
Endocytotic pathway
Retrieval pathways

11. Selective & Specific
Rab proteins
SNARE proteins

12. Rab Proteins

13. SNARE Proteins – mediate vescile fusion
 V-SNAREs – Docking proteins
 T-SNAREs – Latch proteins

14. Botulism & Tetanus
AUTOPHAGY or AUTOPHAGOCYTOSIS

15. FAMILIAL HYPERCHOLESTEROLEMIA

16. A colorized scanning electron microscope picture of a
nerve ending that has been broken open to reveal the
synaptic vesicles (orange and blue) beneath the cell
membrane.