NCBI Summary:
The protein encoded by this gene is a pleiotropic cytokine that functions as a chemoattractant, a modulator of T cell activation, and an inhibitor of HIV replication. The signaling process of this cytokine is mediated by CD4. The product of this gene undergoes proteolytic processing, which is found to yield two functional proteins. The cytokine function is exclusively attributed to the secreted C-terminal peptide, while the N-terminal product may play a role in cell cycle control. Caspase 3 is reported to be involved in the proteolytic processing of this protein. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Feb 2010]
General function
Ligand, Cytokine
Comment
Cellular localization
Secreted
Comment
Ovarian function
Initiation of primordial follicle growth
Comment
Cytokine (IL16) and Tyrphostin Actions on Ovarian Primordial Follicle Development. Feeney A 2014 et al.
An ovarian follicle is composed of an oocyte and surrounding theca and granulosa cells. Oocytes are stored in an arrested state within primordial follicles until they are signaled to re-initiate development by undergoing primordial to primary follicle transition. Previous gene bionetwork analyses of primordial follicle development identified a number of critical cytokine signaling pathways and genes potentially involved in the process. In the current study, candidate regulatory genes and pathways from the gene network analyses were tested for their effects on the formation of primordial follicles (follicle assembly) and on primordial follicle transition using whole ovary organ culture experiments. Observations indicate that the tyrphostin inhibitor BCI increased follicle assembly significantly, supporting a role for the mitogen activated protein kinase (MAPK) signaling pathway in follicle assembly. The cytokine interleukin 16 (IL16) promotes primordial to primary follicle transition as compared to the controls, where as Delta-like 4 (DLL4) and WNT-3A treatment have no effect. Immunohistochemical experiments demonstrated for both the cytokine IL16 and its receptor CD4 localization to the granulosa cells surrounding each oocyte within the ovarian follicle. The tyrphostin LDN193189 (LDN) is an inhibitor of the bone morphogenic protein receptor 1 (BMPR1) within the TGFB signaling pathway and was found to promote the primordial to primary follicle transition. Observations support the importance of cytokines (i.e. IL16) and cytokine signaling pathways in regulating early follicle development. Insights into regulatory factors affecting early primordial follicle development are provided that may associate with ovarian disease and translate to improved therapy in the future.
/////////////////////////