Expression of mannose-6-phosphate receptors during perinatal development in rat organs

JOFRÉ G; CARVELLI L; SARTOR T; SOSA MA

Rosario (Santa Fe)

Congreso; 42th Reunión Anual de la Sociedad Argentina de Investigación Bioquímica (SAIB); 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Lysosomal enzymes (LE) are transported to lysosomes via mannose-6-P receptors (MPRs). Two MPRs have been described; the cation-dependent (CD-MPR) and the cation-independent (CI-MPR), although their co-existence is still unclear. We are interested in knowing whether CD- or CI-MPR (or both) participate in maturation of lysosomal apparatus (LA) during development. We have described that expression of both MPRs varies in rat brain and liver during perinatal development. Here, we extended this study to other organs to determine if variations of MPRs are related with functionality of the organ, and with maturation of LA. By western blot analysis, we measured expression of both receptors in rat organs at different perinatal ages. We observed that variations in both MPRs depend on the organ, as the CD-MPR in kidney (K), lung (L), hearth (H), and thymus (T) was increased at the day 10th after birth, meanwhile in spleen (S) did not change and interestingly this receptor increased in pancreas (P) of 90 day old rats. In turn, CI-MPR expression decreased progressively from newborns to adult rats in the studied organs, except in P where a dramatic increase was observed. The activity of two LE correlated with variations in expression of CD-MPR. We concluded that CD-MPR may be involved in maturation of LA, and CI-MPR is mostly devoted to regulate cell differentiation at early stages of development.