Flashcards in Muscles Deck (30)
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1
Thick filament
Myosin
2
Thin filament
Actin
3
Largest protein known
Titin
4
Arrangements thick and thin filaments
Hexagonal arrangement: each thick filament has 6 thin filaments surrounding it. 6:3 ratio of thin : thick filaments
5
What links actin to Z-lines?
α-actin
6
What genes code for α-actin?
ACTN 1/2/3/4
7
What proteins aid in filament formation and muscle stability?
Actin capping proteins
8
Describe the structure of actin capping proteins?
Heterdimeric complex with α/β subunits
9
Genes that code for actin capping proteins
CAPZA 1/2/3
10
What is the main protein associated with the M line?
Myomesin
11
What genes express myomesin?
MYOM 1/2/3
12
Components of myosin
6 subunits, 2 heavy chains, 2 light chains
13
What digestion sites signify the point of hing in converting ATP hydrolysis into contraction/relaxation?
Trypsin and papain
14
What protein covers the myosin binding site on actin?
Tropomyosin
15
Which protein of troponin bind to Ca/regulates ca dependent muscle contraction?
TropC
16
What protein complex removes the "cover" from the myosin-binding sites of 7 G-actins?
Troponin
17
What are the types of actin?
α, β, ɣ
18
Which actin gene is primarily expressed in skeletal muscle?
ACTA 1
19
Which actin gene is primarily expressed in smooth muscle?
ACTA 2
20
Which actin gene is primarily expressed in cardiac muscle?
ACTC 1
21
Mutations in which genes cause inherited cardiomyopathy?
Troponin I and T
22
Dystrophin-glycoprotein complex
Multi-subunit complex that mediates interactions between cytoskeleton, membrane, and ECM.
23
What gene codes for DGC?
DMD gene on Chromosome X
24
Duchenne muscular dystrophy
X-linked recessive. Primarily expressed in males. S&s appear around 6months or at birth. Wheel chair dependance by 10-12 y/o/ Progressive muscle degeneration/weakness. Life expectancy 25y/o
25
Signs of Duchenne MD
Sway back, child walking on toes, poor balance, thin/weak thighs, belly sticks out, knees may bend back to take weight, difficultly swallowing
26
DMD Pathophysiology
DGC is ineffective. Have an abnormally influx of Ca that leads to cell necrosis
27
Becker Muscular Dystrophy
Milder form of MD. Non-lethal disorder. Muscle weakness is very gradual. Caused by CTG trinucleotide repeat on chromosome 19.
28
Signs of Becker MD
Sustained involuntary contractions, difficultly releasing grip when shaking hands, prominent forehead, narrow face, difficultly swallowing
29
X-linked dilated cardiomyopathy
Cardiac muscle is unable to produce dystrophin due to mutation but skeletal muscle maintains DGC synthesis
30
