Following statements are regarding to gap junctions. i. Vertebrate gap junctions are composed of connexins, a family of structurally related transmembrane proteins with molecular weights between 26,000 and 60,000. ii. Each vertebrate hexagonal particle consists of six noncovalently associated connexin molecules. Each individual connexin molecule has two membrane-spanning α helices with a topology similar to that of claudin. iii. The permeability of gap junctions is regulated by posttranslational modification of connexins (e.g., phosphorylation) and is sensitive to changes in environmental conditions such as intracellular pH and Ca2+ concentration, membrane potential, and the intercellular potential between adjacent interconnected cells (“voltage gating”). iv. The assembly of connexins, their trafficking within cells, and the formation of functional gap junctions apparently depend on N-cadherin and its associated adapter proteins as well as desmosomal proteins. Which of the following statements are correct? -triyambak.org