Ch 12.3 Lysosomes, peroxisomes, vesicular transport across the plasma membrane

Secretory pathway at Golgi

1. constitutive: via ___ synthesized plasma membrane lipids and membrane protein , by default, fusion to plasma membrane

2. regulated: secretory vesicles storing ___ ___ ; regulated by ____ such as hormones or neurotransmitters

newly, unregulated, secretory proteins, signals

Sorting lysosomal enzymes are vesicles with lysosomal enzymes are delivered to either ___ or ___ endosomes. Early endosomes can mature to become ___endosomes or ___

early, late, late, lysosomes

Early and late endosomes mature to become lysosomes by becoming ___ ___. This helps enzymes lose affinity to their ___ and become ___. The receptors are recycled back to the trans-golgi

more acidic, receptors, active

Function of lysosomes is to degrade ___ or ____ organelles (autophagy) and degrade ___ or ___ material (heterophagic)

old, damaged, endocytosed, phagocytosed

lysososmal enzymes are acid hydrolases

• ___= most types

• ___

• ___= least types

• ___

• ____= second most

• ___

proteases, lipases, nucleases, phosphatases, glycosidases, sulfatases

___ catalize hydrolisys (break down) reactions at acidic pH

hydrolases

lysosomal storage disease is a mutation that leads to failure to ____, to be ___ or ___ properly. Most diseases are due to ____ deficiencies, ____ lysosomes. It leads to severe ___ defects, retardation or death at young age

function, expressed, trafficked, glycosides, enlarged, neurological

Lysosomal storage disease are ___ ____

very specific

peroxisomes are small organelles that contain enzymes for ____ foreign molecules, ____ ___ by ___- ____, and ___-containing compound

metabolizing, fatty acids, beta-oxidation, nitrogen

___ produces H2O2 (peroxide)

oxidase

Catalase breaks down hydrogen peroxide to ___ and ____

O2, H2O

up to 50% of peroxisomes, most in the ____, metabolize___ ___ by beta-oxidation

mitochondria, fatty acids

Peroxisomes that contain enzymes for metabolizing nitrogen-containing compounds transfer___ ____ between different molecules

amino groups

endocytosis can be clathrin ____ or ____

• if clathrin independent it can be ____-mediated or non clathrin /non caveolin endocytosis

independent, dependent, caveolin

exocytosis vesicles fuse with ___ ___. transport is ___ of the cell and can be regulated or constitutive

plasma membrane, out,

Constitutive secretion vesicles from the ___ take cargo ____ to the plasma membrane. Cargo can be transmembrane proteins, extra cellular matrix molecules…

trans-golgi, directly

Regulated secretion vesicles from the trans-golgi ____near the plasma memebrane and only fuse in repsose to a ___

park, signal

Clathrin dependent endocytosis

mediated by ___

internalization of nutrients like LDL, Transferrin etc

down-reg of receptors: ___ ___ receptors, ____ receptors ets

basic molecular machinery is the ___ no matter what the cargo is

receptors, growth factor, adrenergic, same

Clatherin-dependent endocytosis steps:

1. receptor binds ___

2. adapter proteins bind ____

3. other membrane ____ ____ bind

4. ____ binds to the adaptor proteins

5. a coated pit begins to form

cargo, receptors, scaffolding proteins, clathrin

endocytosis of LDL

___ particles bind to the ____ ____ in clathrin-coated pit which forms an ___ ___;

receptors are recycled and lysosomes form

LDL, LDL receptor, early endosome,

Familial hypercholesterolemia

a ___ disorder that is caused by defective or absent receptors for ___ on cell surfaces

increase in blood plasma LDLs and by an accumulation of LDLs in the body = ___ ___ and ____ ___ ___

inherited as an ___ ___ trait

metabolic, LDLs, heart attack, coronary heart disease, autosomal dominant

Caveolae stable invagination that have a lot of ____, ____, ___-___ ___, signaling proteins and caveolin

sphingolipids, cholesterol, GPI-anchored proteins

Caveolae is involved in ____ uptake and management, ____ platform, ____, reservoir of membrane surface in cells that are subject to ___ stress such as arterial endothelial cetlls

lipid, signaling, endocytosis, mechanical

knockouts of caveolin display impaired lipid ___, impaired ____ via insulin receptors and nitric oxide synthase

storage, signaling

Endocytosis of caveolae requires membrane scafolfing proteins, dynamin and rearrangemement of actin cytoskelton

specific for certain cargo but don’t know much about it

Caveolin is an ____ membrane protein with large ___ ____, reffered as a coat protein

integral, cytosolic region

Nonclathrin/ noncoveolae endocytosis

observed in vitro when clathrin and caveolae systems have been ___-___

internalizes ____ and associated proteins

knocked-out, lipid rafts

Marcopinocytosis

bulk uptake of ___ and ___

Required polymerization of the ___ ___ to form the pseudopods.

___-presenting dendritic cells ‘ask’ their surroundings for potential invaders

large macropinosome vesicles fuse with ___ leading to digestion

molecular fragments from invading organism can be sent back to the plasma membrane and displayed to other immune cells

fluid, membrane, actin cytoskeleton, antigen, lysosome

phagocytosis

____ mechanism by protists

primary role of ___ , ___ and ___ cells of mammalian immune system

feeding, macrophages, neutrophil, dendritic

Phagocytosis

receptors bind ___ molecules or ___

requires ___ of the cytoskeleton to ‘push’ membrane and form the ____

phagosome forms and fuses with ___ leading to digestion

bacterial, antibodies, polymerization, pseudopod, lysosome