Artículos de revistas
Sphingomyelins and ceramides with very-long-chain PUFA are excluded from lowdensity, raft-like domains in differentiating spermatogenic cells
Santiago Valtierra, Florencia Ximena; Mateos, Melina Valeria; Aveldaño, Marta Isabel; Oresti, Gerardo Martin; Sphingomyelins and ceramides with very-long-chain PUFA are excluded from lowdensity, raft-like domains in differentiating spermatogenic cells; American Society for Biochemistry and Molecular Biology; Jlr Papers In Press; 58; 12-1-2017; 529-542
Santiago Valtierra, Florencia Ximena
Mateos, Melina Valeria
Aveldaño, Marta Isabel
Oresti, Gerardo Martin
Rat spermatogenic cells contain sphingomyelins (SM) and ceramides (Cer) with very long chain (VLC) PUFA, in nonhydroxylated (n-V) and 2-hydroxylated (h-V) forms. How these atypical species distribute among membrane fractions during differentiation was investigated here using a detergent-free procedure to isolate a small light, raft-like, low density (L) fraction and a large heavy (H) fraction, mostly derived from the plasma membrane, of spermatocytes, round, and late spermatids. The L fraction contained cholesterol, glycerophospholipids and SM with the same saturated fatty acids in all three stages. In the H fraction, as PUFA increased in the glycerophospholipid and VLCPUFA in SM from spermatocytes to spermatids, the concentration of cholesterol also augmented. The H fraction had mostly n-V SM in spermatocytes but accumulated h-V SM and h-V Cer in spermatids. A fraction containing intracellular membranes had less SM and more Cer than H, but in both fractions SM and Cer species with h-V increased over species with n-V with differentiation. This accretion of h-V was consistent with the differentiation-dependent expression of fatty acid 2-hydroxylase (Fa2h), as it increased significantly from spermatocytes to spermatids. The non-raft region of the plasma membrane is thus the main target of the dynamic lipid synthesis and remodeling that is involved in germ cell differentiation.