Caveolin-1alpha and -1beta perform nonredundant roles in early vertebrate development.
Caveolins are integral membrane proteins that localize predominantly to lipid rafts, where they oligomerize to form flask-shaped organelles termed caveolae and play important roles in membrane trafficking, signal transduction, and other cellular processes. To investigate potential roles for caveolin-1 (cav-1) in development, cav-1alpha and -1beta cDNAs were functionally characterized in the zebrafish. Cav-1alpha and -1beta mRNAs exhibited overlapping but distinct expression patterns throughout embryogenesis. Targeted depletion of either Cav-1 isoform, using antisense morpholino oligomers, resulted in a substantial loss of caveolae and dramatic neural, eye, and somite defects by 12 hours after fertilization, the time at which mRNA levels of both isoforms substantially increased in wild-type animals. Morphant phenotypes were rescued by injection of homotypic (cav-1alpha/cav-1alpha) but not heterotypic (cav-1alpha/cav-1beta) zebrafish and human cav-1 cRNAs, revealing nonredundant and evolutionarily conserved functions for the individual Cav-1 isoforms. Mutation of a known Cav-1 phosphorylation site unique to Cav-1alpha (Y14-->F) resulted in a failure to rescue the cav-1alpha morphant phenotype, verifying an essential role for Cav-1alpha specifically and implicating this residue in early developmental functions. Cav-1alpha and -1beta morphants also exhibited disruption in the actin cytoskeleton. These results support important and previously unanticipated roles for the Caveolin-1 isoforms in vertebrate organogenesis.
Fang
Ping-Ke
PK
Urological Diseases Research Center, Department of Orthopaedic Surgery, Children's Hospital Boston, Harvard Medical School, Enders Research Laboratories, Suite 1161, 300 Longwood Ave., Boston, MA 02115, USA.
Solomon
Keith R
KR
Zhuang
Liyan
L
Qi
Maosong
M
McKee
Mary
M
Freeman
Michael R
MR
Yelick
Pamela C
PC
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning; D021941:Caveolae / Q000737:chemistry; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009672:Notochord / Q000098:blood supply / Q000196:embryology; D010766:Phosphorylation; D020033:Protein Isoforms; D012333:RNA, Messenger; D017386:Sequence Homology, Amino Acid; D019170:Somites / Q000378:metabolism; D014018:Tissue Distribution; D014162:Transfection; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000502:physiology*
D000199:Actins; D051242:Caveolin 1; D020033:Protein Isoforms; D012333:RNA, Messenger; D029961:Zebrafish Proteins