CASK (calmodulin sensitive kinase) is a ~112kDa member of the membrane associated quanylate kinase (MAGUK)
protein family. It is an adaptor protein with a
calcium/calmodulin-dependent protein kinase domain, a
SH3 domain, aguanylate kinase homology domain (GUK)
and a PDZ domain. CASK links transmembrane proteins
to the cytoskeleton and signaling molecules. In
particular, CASK binds to Neurexin to stabilize pre- and
post-synaptic structrures (1). While most of CASK proteins
are cytoplasmic, a portion of the protein enters the
nucleus, where it acts as a transcriptional co-activator (2).
Manifesting the importance of CASK, transgenic mice with
insertional mutations die within 24 hours of births (3).
CASK is also localized in the nuclei of basal keratinocytes
in newborn rodent skin and developing hair follicles. It
may play a role in wound healing (4).