STRN (striatin, calmodulin binding protein)

2p22.2

Composed of a caveolin-binding domain, a coiled-coil domain, a calmodulin-binding domain, and at least 6 WD-repeats. Striatin (STRN) binds many proteins, and forms multi-protein complexes. It is a scaffolding protein; striatin contains a caveolin-binding consensus motif, and binds caveolin-1, the major protein involved in caveolae and lipid rafts. Striatin is also involved in signaling and trafficking in a Ca²⁺ dependant manner, exhibiting a dual role in endocytic process and signaling.

PDGFRA (platelet-derived growth factor receptor, alpha polypeptide)

4q12

Composed of an extracellular domain (the immunoglobulin-like motifs), a transmembrane domain, with an inhibitory juxtamembrane WW-like domain (Irusta et al., 2002), and an intracellular domain (kinase domain) Receptor tyrosine kinase; forms homodimer, and heterodimer with PDGFRB; dimerization induces kinase domain activation, leading to the activation of intracellular signalling pathways (Kawagishi et al., 1995).

Hybrid genes between various partners and PDFRGA occur in chronic myeloid leukaemia-like diseases with eosinophilia, mostly chronic eosinophilic leukemia (CEL), a clonal hypereosinophilic syndrome. PDGFRA partners known so far are: STRN (2p24), herein described (Curtis et al., 2007), FIP1L1 (4q12) (Cools et al., 2003; Pardanani et al., 2004), CDK5RAP2 (9q33) (Walz et al., 2006), KIF5B (10p11) (Score et al., 2006), ETV6 (12p13) (Curtis et al., 2007), and BCR (22q11) (Baxter et al., 2002).
Mutations of platelet-derived growth factor receptor-alpha (PDGFRA) are observed in a subset of gastrointestinal stromal tumors (GISTs) (Heinrich et al., 2003).
Tumours with PDGFRA involvement are responsive to imatinib therapy (Cools et al., 2003; Debiec-Rychter et al., 2004).