Altered Membrane Mechanics Provides a Receptor‐Independent Pathway for Serotonin Action.

Dey, Simli; Surendran, Dayana; Engberg, Oskar; Gupta, Ankur; Fanibunda, Sashaina E.; Das, Anirban; Maity, Barun Kumar; Dey, Arpan; Visvakarma, Vicky; Kallianpur, Mamata; Scheidt, Holger A.; Walker, Gilbert; Vaidya, Vidita A.; Huster, Daniel; Maiti, Sudipta

Serotonin, an important signaling molecule in humans, has an unexpectedly high lipid membrane affinity. The significance of this finding has evoked considerable speculation. Here we show that membrane binding by serotonin can directly modulate membrane properties and cellular function, providing an activity pathway completely independent of serotonin receptors. Atomic force microscopy shows that serotonin makes artificial lipid bilayers softer, and induces nucleation of liquid disordered domains inside the raft‐like liquid‐ordered domains. Solid‐state NMR spectroscopy corroborates this data at the atomic level, revealing a homogeneous decrease in the order parameter of the lipid chains in the presence of serotonin. In the RN46A immortalized serotonergic neuronal cell line, extracellular serotonin enhances transferrin receptor endocytosis, even in the presence of broad‐spectrum serotonin receptor and transporter inhibitors. Similarly, it increases the membrane binding and internalization of oligomeric peptides. Our results uncover a mode of serotonin–membrane interaction that can potentiate key cellular processes in a receptor‐independent fashion.

SEROTONIN; BILAYER lipid membranes; SEROTONIN receptors; ATOMIC force microscopy; TRANSFERRIN receptors; TRANSFERRIN

Chemistry - A European Journal, 2021, Vol 27, Issue 27, p7533

0947-6539

Academic Journal

10.1002/chem.202100328