Molecular characterization and immunohistochemical localization of palmdelphin, a cytosolic isoform of the paralemmin protein family implicated in membrane dynamics

Cellular and subcellular localization of paralemmin-1, a protein involved in cell shape control, in the rat brain, adrenal gland and kidney

“…Palmdelphin, on the other hand, shares more sequence motifs with paralemmin-1 than does paralemmin-3, but the C-terminal lipidation motif is replaced by an unrelated sequence. Accordingly, palmdelphin behaves as a predominantly cytosolic protein in subcellular fractionation (Hu et al 2001), and no plasma membrane association was seen in immunomorphology (Hu et al 2005). However, immunoelectron microscopy in the brain demonstrated a spotted pattern of distribution in the cytoplasm of neuronal cell bodies and dendrites, including spines (Hu et al 2005), which is very similar to that of paralemmin-1.…”

“…Accordingly, palmdelphin behaves as a predominantly cytosolic protein in subcellular fractionation (Hu et al 2001), and no plasma membrane association was seen in immunomorphology (Hu et al 2005). However, immunoelectron microscopy in the brain demonstrated a spotted pattern of distribution in the cytoplasm of neuronal cell bodies and dendrites, including spines (Hu et al 2005), which is very similar to that of paralemmin-1. Moreover, cytosolic palmdelphin could be partially recruited to a membrane/cytoskeletal preparation of COS cell ghosts, and the cell ghost-recruited palmdelphin was partially resistant to Triton X-100 extraction, reminiscent of a lipid raft-associated protein (Hu et al 2005).…”

“…1b) and in immunohistochemistry (light and electron microscopies, data not shown). Conversely, antipalmdelphin staining was blocked by recombinant palmdelphin but not by paralemmin-1 (Hu et al 2005). Pre-immune sera did not produce the characteristic paralemmin-1 staining patterns, on western blots ( Fig.…”

“…As described earlier (Kutzleb et al 1998), paralemmin-1 displays a characteristic multi-band pattern on brain western blots. This molecular heterogeneity is much higher in the brain than in other tissues, and diVerential splicing (+/¡ exon 8, corresponding to the upper and lower group of bands), lipidation, phosphorylation and apparently additional, unidentiWed forms of posttranslational modiWcation are known to contribute to it (Kutzleb et al 1998;Hu et al 2005). Immunostaining was abolished by pre-incubation of the antibody with recombinant paralemmin-1 (amino acids 15-242) but not by the recombinant isoform, mouse palmdelphin (full length), both on western blots (Fig.…”

“…Paralemmin-3, Wrst described in Xenopus laevis as Xlgv7/ Xlcaax-1, has been implicated in the diVerentiation or morphogenesis of epithelia (Cornish et al 1992). The fourth family member, palmdelphin, lacks the C-terminal lipid anchor with which the other three isoforms are endowed and is largely cytosolic (Hu et al 2001(Hu et al , 2005. In the expressed sequence tag database, paralemmin-1 and palmdelphin cDNAs are of similar frequencies, whereas paralemmin-2 and paralemmin-3 are one order of magnitude less abundant.…”