RANKL Function — MFDS Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

ModeratePhysiologyRANKL FunctionMFDS Part 1

Which signalling molecule binds to RANK on osteoclast precursors and promotes their differentiation into mature osteoclasts?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — RANKL

RANKL is the ligand for RANK, a receptor expressed on osteoclast precursors. RANKL–RANK signalling activates intracellular pathways that promote osteoclast differentiation, activation and survival, thereby supporting bone resorption. Calcitonin instead binds receptors on mature osteoclasts and inhibits their resorptive activity. Oestrogen generally restrains osteoclast formation and survival rather than activating RANK. Insulin and growth hormone influence skeletal metabolism and growth but are not ligands for RANK and do not initiate the defining RANK-dependent osteoclastogenic pathway. Therefore, RANKL is the single best answer.

Reference: Park JH, Lee NK, Lee SY. Current Understanding of RANK Signaling in Osteoclast Differentiation and Maturation. Mol Cells. 2017;40(10):706-713. https://pubmed.ncbi.nlm.nih.gov/29047262/