All Peptide Hormones after Cell Function by Phosphorylation, while Essay

All Peptide Hormones after Cell Function by Phosphorylation, while Steroid Act by Alerting Gene Expression - Essay Example For instance, endocrine signaling involves the secretion of specific hormonal signals in the blood stream which are then distributed to other parts of the body. The first messenger molecule cannot pass through the target cell membrane, but instead are bound by specific receptors. Intracellular communication takes place when receptors activate secondary messengers or signaling proteins which convey those signals through chemical reaction to the nucleus of the cell (Marks, 2008). Proteins are the key signal processors in a cell. The incredible structural flexibility and chemical reactivity offers characteristic signal transduction property i.e., signals movement inside from outside of the cell, to all proteins. The input signals allow conformational changes in the structure altering the specific protein functions and cellular activity. Proteins capable of binding to a phosphate molecule are called phospho-proteins, and play a central role in the signaling pathway regulating various cel lular processes. Protein phosphorylation or phosphoregulation is a reversible process which regulates the protein function by covalent modification. To switch between phosphorylized and dephosphorylized states, specific kinase (tyrosine, serine/threonine) and phosphatase enzymes act respectively. Phosphorylation may either increase or decrease activity depending on specific type of enzyme. The affinity towards interacting cohort protein, enzymatic action, and subcellular localization and other functional changes are altered by protein phosphorylation (Goto, Kiyono and Inagaki, 2007). As a signaling molecule, proteins have a receiver and a transmitter module. In order to recognize and decode a specific signal, the receiver requires prior information for that signal which has to be either obtained or is genetically fixed. To coordinate signal and its exact implication, differentiation occurs exclusively in the receptor cells or target proteins. For instance, adrenaline hormonal signal has different meanings for different target tissues or target proteins control various functional consequences of phosphorylation. The intercellular signaling molecules including peptides, amino acids, amines and proteins cannot enter cell membrane and thus interact with receptors on the surface. The output signal transduction in receptor proteins results in a conformational alterations which are then differentiated by other signal transducing proteins along the pathway such as G-proteins. The chemical interactions taking place as a result of signal reception are not definite sequences, but rather diffused and complex excitation patterns (King, 2012). The hormones secreted by endocrine tissues get attached to particular plasma carrier proteins and composites are then distributed to distant parts. The receptors in the responding tissues have very high affinity for hormones and regulate metabolism of target through a coupled process. The receptors for amino acid and peptide hormones are mostly present on the cell membrane. Signal transducing receptors are classified into receptors with ability to enter cell membrane such as tyrosine kinases, tyrosine phosphatases and serine/threonine kinases, serpentine receptors which are coupled such as adrenergic and odorant receptors, and nuclear or intracellular receptors such as steroid