Sorting of both soluble and integral membrane proteins is disrupted by loss of ADF/cofilin, suggesting that actin severing controls expansion of a sorting domain within the TGN.

Protein transport between the trans-Golgi network and endosomes is mediated by transport vesicles formed by the adaptor-protein complex AP-1, consisting of the adaptins g1, b1, m1, s1. Mammalia express m1A ubiquitously and isoform m1B in polarized epithelia. Mouse g1 or m1A 'knock out's revealed that AP-1 is indispensable for embryonic development. We isolated m1A and m1B from Danio rerio. Analysis of m1A and m1B expression revealed tissue-specific expression for either one during embryogenesis and in adult tissues in contrast to their expression in mammalia. m1B transcript was detected in organs of endodermal derivation and ''knock-down'' experiments gave rise to embryos defective in formation of intestine, liver, and pronephric ducts. Development ceased at 7-8 dpf. m1B is not expressed in murine liver, indicating loss of m1B expression and establishment of alternative sorting mechanisms during mammalian development. Developmental Dynamics 239:2404-2412,