PECAM-1 full-length and mutant constructs.

Schematic representation and calcium signaling and SH2 protein interaction characteristics of the PECAM-1 constructs described in the text. RHP indicates full-length human PECAM-1. The extracellular domain containing 6 Ig-like loops is represented as filled ovals 1-6, the transmembrane domain as a rectangle, and the cytoplasmic domain as a gray rectangle, representing cytoplasmic exons 9-16. PITC is a chimeric construct containing an intact PECAM-1 extracellular domain fused to the nonhomologous ICAM-1 transmembrane and cytoplasmic domains. PECAM-ΔCD is a deletion construct lacking the PECAM-1 cytoplasmic domain. AAAA is a cytoplasmic domain deletion construct, encoding only 9 cytoplasmic amino acid residues, with a mutation in the membrane proximal sequence (KCYFLRKAK→KCYFLAAAA) that disrupts cell border localization. All stably transfected cell lines, but not untransfected REN, uniformly express PECAM-1 (> 95% cells) at levels similar to that of RHP.