Fig. 1. Constructs used for analysis of human proSP-C trafficking. SP-C inserts containing wild-type or mutant human SP-C were generated by PCR and subcloned into either the EGFPC₁ or pcDNA3 vectors as described in Materials and Methods. From top to bottom: hSP-C^1-197 construct inserted into pcDNA3 containing full-length human SP-C shown with putative intrachain disulfide bonding between cys189 and cys120/121; EGFP/SP-C^1-197 created by ligation of PCR generated hSP-C^1-197 insert into the pEGFPC₁ vector; EGFP/hSP-C^Exon4 is a deletional construct produced by removal of amino acids 110-144 encoded by Exon 4, which includes cys121/122; EGFP/hSP-C^C120/121G is a double cysteine folding mutant containing Gly for Cys substitutions at residues 120 and 121 in the COOH flanking propeptide; EGFP/hSP-C^{C120/121/189G} contains substitutions of Gly for Cys at codons 120, 121 and 189; HA/hSP-C^1-197 is a full-length human SP-C cDNA containing the HA sequence peptide linked to the N-terminus and subcloned into pcDNA3. Amino acid nomenclature is based on published human SP-C sequence.