Q.54 Which of the following statement(s) regarding trafficking in eukaryotic cells
is(are) CORRECT?
(A) Dynamin binds GTP and is involved in vesicle budding
(B) Dynamin is involved in cytoskeletal remodelling
(C) Dynein binds ATP and is involved in movement of organelles along
microtubules
(D) Dynein binds GTP and is involved in movement of organelles along
microtubules
Mastering Eukaryotic Cell Trafficking: Dynamin, Dynein, and Vesicle Dynamics Explained
Eukaryotic cell trafficking relies on precise molecular motors and GTPases for vesicle budding and organelle transport. The correct statements are (C) and (D) is incorrect due to dynein’s ATP specificity.
Correct Answer
C only. Dynein binds ATP to power organelle movement along microtubules, distinguishing it from GTPases like dynamin.
Option Breakdown
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(A) Incorrect: Dynamin binds GTP for vesicle scission, not budding initiation; it pinches off necks of clathrin-coated pits after budding.
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(B) Incorrect: Dynamin primarily drives endocytosis via GTP hydrolysis; cytoskeletal remodeling involves actin or microtubule motors, not dynamin.
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**(C) Correct: Dynein, an AAA+ ATPase, hydrolyzes ATP to transport vesicles and organelles toward microtubule minus-ends, as in ER-to-Golgi traffic.
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(D) Incorrect: Dynein uses ATP, not GTP; GTP-binding is for small G-proteins like Rab in tethering.
Key Mechanisms
Vesicle trafficking separates budding (coat proteins like clathrin/COP), scission (dynamin-GTP), and transport (dynein-ATP on microtubules).
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Dynamin assembles helical collars around vesicle necks, hydrolyzing GTP for fission.
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Dynein-dynactin complexes link cargo to microtubules, enabling retrograde motility.
Exam Insights
This question tests nucleotide specificity: GTPases (dynamin, Rab) vs. ATPases (myosins, kinesins, dynein). Focus on dynamin’s endocytosis role over budding claims.
