# The cadherin domains and the kinesin-binding intracellular domain of CASY-1/calsyntenin function in a redundant manner for learning

## TL;DR

The study shows that two parts of the CASY-1 protein work together to support learning in C. elegans, even if each part alone is not essential.

## Contribution

The paper reveals functional redundancy in CASY-1 domains for learning, providing new insights into its transport mechanism.

## Key findings

- The cadherin domains and kinesin-binding domain of CASY-1 are individually dispensable for learning.
- Simultaneous loss of both domains abolishes CASY-1 function, indicating functional redundancy.
- CASY-1 supports robust transport through multiple protein interactions.

## Abstract

Taste avoidance learning in

Caenorhabditis elegans

is regulated by the calsyntenin/alcadein homolog
CASY-1
, which transports the insulin receptor DAF-2c to the synaptic region. This transport involves binding of the
CASY-1
intracellular domain to the kinesin-1 (KIF5) complex. However, a previous study showed that the intracellular domain of
CASY-1
is dispensable for learning. To investigate how
CASY-1
functions, we performed functional domain mapping of
CASY-1
. Both the cadherin domains of
CASY-1
and its binding to kinesin-1 are individually dispensable, while simultaneous loss of both abolished the
CASY-1
function, suggesting that
CASY-1
enables robust intracellular transport through physical interactions with multiple proteins.