Figure 1.

Alternative splicing of SCF. Alternative splicing of the sixth exon of SCF mRNA produces two membrane bound forms, SCF²⁴⁸ and SCF²²⁰. SCF248 is cleaved by proteases in the domain encoded by exon 6 ( ) to produce a soluble 165 amino acid protein (SCF165 or sSCF). SCF220 or mSCF remains membrane-bound as it lacks the proteolytic cleavage site encoded by exon 6, but it may also be shed in the region encoded by exon 7 to produce a soluble form [10].