FIGURE 1.

Kalirin and the Sec14 superfamily. A, schematic illustrating use of four different Kalrn promoters, which encode alternate first exons (Ex1A, Ex1B, Ex1C, and Ex1D); the CRAL_TRIO domain begins in exon 2, which is common to transcripts initiated at each of the promoters. Alternative splicing generates transcripts encoding Kal7, Kal9, and Kal12, which each terminate with exons encoding unique 3′-untranslated regions. B, Sec14 superfamily members include a CRAL_TRIO domain, which typically binds hydrophobic ligands; some Sec14 superfamily members also include a CRAL_TRIO_N domain. C, multiple sequence/structural alignment for several CRAL_TRIO domains; residues known or predicted to form α-helices (blue) and β-sheets (red) are identified. Structures are known for yeast Sec14p (ID, 6323725; Protein Data Bank entry 1AUA; helices and β-strands shown above the alignment), neurofibromin 1 (NF1) (ID: 119600680; Protein Data Bank entry 3P7Z), and α-TTP (ID: 4507723; Protein Data Bank entry 1OIP). Secondary structures for the CRAL_TRIO regions of kalirin (ID: 295054252), Mcf2l (ID: 341940943; also known as Dbs and Ost), and Trio (ID: 257051075) were predicted using the Phyre2 modeling program. Dashes were inserted to optimize alignment; The GenBank^TM position number of the final residue shown for each protein is given at the right.