Cellular effects of metals Flashcards
What is the role of metal homeostatis in cells?
It maintains balance, preventing deficiencies or toxic excess by regulating metal ion influx, efflux, and intracellular trafficking.
Why is Copper considered an essential nutrient?
Cu supports enzymatic functions and is involved in critical processes like mitochondrial respiration and antioxidant defense
What is the function of metallothioneins in cells?
Metallothioneins bind metals like zinc and copper to regulate their availability and protect cells from toxic metal exposure.
PROTECT CELLS FROM TOXIC METAL EXPOSURE BY BINDING TO THEM
How do toxic metals “hijack” cellular systems?
e.g. Mercury mimics essential ions using existing transporters to enter cells and disrupt normal function
What existing channels do toxic metals use to enter cells?
e.g. NA+ & Ca2+ channels
What are the key intracellular carriers for copper?
Proteins like Atox1, Cox17, and Sco1 facilitate copper trafficking to organelles like mitochondria and the Golgi apparatus.
How does Mercury enter cells?
Can enter via epithelial Ca2+ channel, diffuse as neutral complexes or mimic amino acids for transport
What are the effects of copper overload in cells?
Excess copper generates oxidative stress
producing harmful reactive oxygen species (ROS)
Name 2 cellular defenses against metal toxicity
Metallothioneins
Antioxidant enzymes to neutralize oxidative damage
How does methylmercury mimic essential molecules?
Methylmercury mimics methionine, using amino acid transporters for cellular uptake
What is the Haber-Weiss reaction, and its relevance to copper toxicity?
It is a chemical reaction CATALYZED by copper that produces hydroxyl radicals, contributing to oxidative stress in cells
What is the role of MerP in bacteria?
MerP is a mercury-binding protein that aids i mercury resistance by sequestering HG2+ ions
How do cells respond to metal-induced oxidative stress?
They deplete glutathione, increase antioxidant enzymes and synthesize specific metal-binding proteins
What is the significance of ion channels in metal toxicity?
Toxic metals exploit ion channels to gain entry into cells
How do cells precisely control metal trafficking?
use specific transport proteins and peptides to regulate metal localization and concentration within cellular components
