Rab37Regulates Cell Proliferation And Autophagy

Swamp eel or the rice field eel (Monopterus albus) is a naturally sex-reversal fresh water bony fish. In their early stage of life, swamp eels all are female. After spawn, they will go through a special stage of intersex with ovotestis. and then their gonads will gradually transform into a testis. After this stage, they all become males. This developmental process provides an ideal model for studying sexual development and differentiation. Using the2D-gel electrophoresis, we identified Rab37, an differentiatly expressed gene among gonadal transformations. Rab37was higher expressed in female gonad in both mouse and swamp eel.We identified a shorter transcript of Rab37in mouse, and the shorter transcript can regulated stability of wild type Rab37. A region (the N-terminal) of interaction between Rab family menbers was observed, however the specificity of the interaction is determined by C-terminal.We showed that Rab37can regulate cell proliferation and cell cycle of HeLa cells. Overexpression of Rab37reduced the growth and increased the proportion in S-phase of HeLa cells. Interference of Rab37increased cell proliferation of HeLa cells. In vivo experiment in nude mouse showed that overexpression of Rab37reduced tumor growth in mouse, and interference of Rab37promoted the growth.We indentified the interaction between Rab37and some autophagy proteins. Under the condition of starvation. Rab37was colocated at autophagosome with Atg5and LC3B. and regulated the autophagy. Overexpression of Rab37increased aotophagy in cells. We observed a stronger interaction between Rab37mutant of GTP stable state and Atg5than between Rab37mutant of GDP stable state and Atg5. More autophagosomes were also observed with GTP stable state than GDP stable state of Rab37. Rab37interaction with Atg5recruited LC3B to form autophagosome.