VESICULAR

TRANSPORT

INTRODUCTION

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

INTRODUCTION Transport across but not through the

membrane

Mode of transport of macromolecules

Requires metabolic energy but is independent of concentration gradient

CATEGORIES ENDOCYTOSIS

EXOCYTOSIS

TRANSCYTOSIS

ENDOCYTOSIS TYPES Phagocytosis- cell eating

Pinocytosis- cell drinking Receptor-mediated

ENDOCYTOSIS

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

Clathrin-mediated endocytosis

Clathrin coated vesicles – COP I & COP II

Clathrin

Adaptor Proteins

Dynamin Pinchase

Clathrin-mediated endocytosis

EXOCYTOSIS Non-Constitutive / Regulated

Pathway

Constitutive Pathway

Exocytosis-Endocytosis coupling maintains the surface area of the cell at its normal size.

INTRA CELLULAR VESICULAR TRAFFIC

Biosynthetic- Secretory pathway

Endocytotic pathway

Retrieval pathways

Vesicular traffic occurs in an orderly fashion

Selective & Specific

Rab proteins

SNARE proteins

Rab Proteins

SNARE Proteins – mediate vescile fusion

V-SNAREs – Docking proteins T-SNAREs – Latch proteins

APPLIED ASPECTSBotulism & Tetanus

AUTOPHAGY or AUTOPHAGOCYTOSIS

APPLIED ASPECTS

FAMILIAL HYPERCHOLESTEROLEMIA

THANK YOU

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.