Alladi Ramakrishnan Hall

To Stick or to Sever - Resolving the Adhesion Conundrum during Cell Division

Anup Padmanabhan

Ashoka University, Sonipat

To maintain tissue integrity, cell division in many tissue types have to ensure that the inter-cellular adhesion is not compromised. This results in an interesting cellular conundrum. While the division apparatus is trying to pull the furrow inwards, the cell adhesion proteins on the surface are engaged with receptors presented on neighbouring cells, effectively resisting the inward pull of cytokinetic furrow. A ’tug of war’ model is an attractive idea where the cytokinesis proceeds when the contractile force of furrow exceeds that of the inter cellular adhesion. We think there is more to it. Our work on cytokinesis in the C. elegans zygote uncovered an additional mechanism, that the cells might be employing in resolving this conundrum.

Specifically, we wanted to know

(1) how cell adhesion receptors modulate cytokinesis dynamics, and,

(2) how cells manage their adhesion receptors during cell division.

We observed that, cell adhesion receptors slowed down the rate of cytokinesis, by associating with actin cytoskeleton and reducing the motor activity of myosin at the cell surface. This mode of regulation is independent of its cell-adhesion function.

We also discovered that the actin architecture at the division site restricts mobility of cell adhesion receptors, thereby excluding cell adhesion activity at the site of division.

Taken together, we believe, we have discovered a rather fascinating phenomenon of reciprocal antagonism between the cell division and the cell adhesion processes.