Which of the following statement(s) regarding trafficking in eukaryotic cells is(are) CORRECT?
Dynamin binds GTP and is involved in vesicle budding
Dynamin is involved in cytoskeletal remodelling
Dynein binds ATP and is involved in movement of organelles along microtubules
Dynein binds GTP and is involved in movement of organelles along microtubules
ANSWER
A, C — Dynamin binds GTP and drives vesicle budding/scission (A); dynein is an ATP-driven motor for organelle movement along microtubules (C). B and D misassign the nucleotide/function.
Official answer: A, CSource: Official answer key, GATE 2022 BT (IIT Kharagpur)
MSQ, 2 marks: the question asks which statement(s) about trafficking in eukaryotic cells are CORRECT.
Option A: Dynamin is a large GTPase that hydrolyzes GTP to drive the mechanical scission (pinching-off) of clathrin-coated vesicles from the plasma membrane during endocytosis — its textbook-defining function in vesicle budding. A is CORRECT.
Option B: Dynamin's defining trafficking role is vesicle scission, not cytoskeletal remodelling; actin/microtubule reorganisation is handled by other GTPases (e.g., Rho family) and motor proteins (myosin/kinesin/dynein), not dynamin. B is INCORRECT.
Option C: Dynein is an ATPase motor protein that hydrolyzes ATP to walk along microtubules, moving cargo/organelles (typically toward the microtubule minus end, i.e. retrograde transport). C is CORRECT.
Option D: Dynein binds and hydrolyzes ATP, not GTP — pairing dynein with GTP-binding misassigns its nucleotide. D is INCORRECT.
Conclusion: A and C correctly pair each protein (dynamin, dynein) with its correct nucleotide (GTP, ATP) and correct trafficking/motor function; B and D misassign the roles. Final answer: A, C.
KEY IDEA
Dynamin is a large GTPase that pinches off vesicles (endocytosis/budding); dynein is an ATPase motor that moves cargo/organelles along microtubules (typically toward the minus end). Kinesin, by contrast, generally moves cargo toward the microtubule plus end, and neither motor's nucleotide is interchangeable with the other's.
WATCH OUT FOR
Confusing the nucleotide used by motor/mechanoenzyme proteins — assuming all motor and trafficking proteins use ATP (missing that dynamin is a GTPase) or, conversely, assigning GTP to dynein (option D) by analogy with other GTP-binding trafficking regulators (e.g., Rab or Arf GTPases). Also mistakenly crediting dynamin with a general cytoskeletal remodelling role (option B) rather than its specific, well-defined function in vesicle scission.
From the GATE 2022 BT paper. Every question of this paper · Download the full paper · All 15 Cell biology questions, with notes
