Developmental differences between cation-independent and cation-dependent mannose-6-phosphate receptors in rat brain at perinatal stages.
Mannose-6-phosphate receptors (MPRs) play a role in the selective transport of macromolecules bearing mannose-6-phosphate residue to lysosomes. To date, two types of MPRs have been described in most of cells and tissues: the cation-dependent (CD-MPR) and cation-independent mannose-6-phosphate receptor (CI-MPR). In order to elucidate their possible role in the central nervous system, the expression and binding properties of both MPRs were studied in rat brain along perinatal development. It was observed that the expression of CI-MPR decreases progressively from fetuses to adults, while the CD-MPR increases around the 10th day of birth, and maintains these values up to adulthood. Binding assays showed differences in the Bmax and KD values between the ages studied, and they did not correlate with the expression levels of both MPRs. Variations in lysosomal enzyme activities and expression of phosphomannosylated ligands during development correlated more with CD-MPR than with CI-MPR expression. These results suggest that both receptors play a different role in rat brain during perinatal development, being CD-MPR mostly involved in lysosome maturation.
Instituto de Histología y Embriología (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, Centro Universitario, Parque General San Martín, (5500) Mendoza, Argentina.
P S
PS
Romano
L
L
Carvelli
A C
AC
López
G
G
Jofré
T
T
Sartor
M A
MA
Sosa
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D015153:Blotting, Western / Q000379:methods; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002352:Carrier Proteins; D002412:Cations / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005966:Glucuronidase / Q000378:metabolism / Q000493:pharmacokinetics; D006868:Hydrolysis; D046911:Macromolecular Substances; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017527:Receptor, IGF Type 2 / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology
D002352:Carrier Proteins; D002412:Cations; D046911:Macromolecular Substances; D017527:Receptor, IGF Type 2; D005966:Glucuronidase